bull ARTICLES bullmiddot SPECIAL TOPIC middot Electrochemical Power Sources

December 2017 Vol60 No121540ndash1545doi 101007s11426-017-9156-0

CeO2NiCo2O4 nanowire arrays on carbon textiles as highperformance cathode for Li-O2 batteries

Zhen-Dong Yang12dagger Zhi-Wen Chang13dagger Ji-Jing Xu1 Xiao-Yang Yang12 amp Xin-Bo Zhang1

1State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of SciencesChangchun 130022 China

2Key Laboratory of Automobile Materials (Jilin University) Ministry of Education Department of Materials Science and Engineering JilinUniversity Changchun 130022 China

3University of Chinese Academy of Sciences Beijing 100049 China

Received August 10 2017 accepted October 15 2017 published online November 17 2017

The successful development of Li-O2 battery technology depends on developing a stable and efficient cathode As an importantstep toward this goal for the first time we report the development of CeO2 nanoparticles modified NiCo2O4 nanowire arrays(NWAs) grown on the carbon textiles as a new carbon-free and binder-free cathode system In this study the Li-O2 battery withthe CeO2NiCo2O4 NWAs has exhibited much reduced overpotentials a high discharge capacity an improved cycling stabilityoutperforming the Li-O2 battery with NiCo2O4 NWAs These improvements can be attributed to both the tailored morphology ofdischarge product and improved oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activity after CeO2 NPsdeposition To a considerable extent this idea of cathode construction including structure design and composition optimizationcan provide guidance for further researches in developing more powerful cathode for Li-O2 battery

Li-O2 battery efficient cathode design CeO2 nanoparticles NiCo2O4 nanowire arrays improved electrochemicalperformances

Citation Yang ZD Chang ZW Xu JJ Yang XY Zhang XB CeO2NiCo2O4 nanowire arrays on carbon textiles as high performance cathode for Li-O2 batteriesSci China Chem 2017 60 1540ndash1545 doi 101007s11426-017-9156-0

1 Introduction

Rechargeable lithium-oxygen (Li-O2) batteries have receivedrapidly growing attention because of their high theoretical en-ergy density (3600 W h kgminus1) which is viewed as a promisingalternative to gasoline [1ndash6] To realize their practical ap-plication numerous efforts have been devoted into the Li-O2

field since the demonstrated rechargeability by Bruce in 2006[7] To date great achievements in improving the perfor-mances of Li-O2 battery have been made however its devel-opment is still at the infant stage Many scientific and techno-

daggerThese authors contributed equally to this workCorresponding author (email xbzhangciacaccn)

logical challenges such as low round-trip efficiency low ratecapability and a poor cycle life need to be overcome beforeits final commercialization [89] To address these challengesthe construction of an efficient cathode is necessary since thecathode properties can affect the Li-O2 reactions significantly[10]In light of previous results an ideal oxygen cathode re-

quires a highly conductive and porous structure to promotethe mass transfer of all reactants and house the generatedLi2O2 [1112] So far many carbonaceous cathodes with ad-vanced architecture have been reported [1314] Regretfullythese carbonaceous materials can be easily degraded upon theattack of the highly oxidative oxygen species (Li2O2 or its in-termediate LiO2) resulting in the formation and accumulation

copy Science China Press and Springer-Verlag GmbH Germany 2017 chemscichinacom linkspringercom

SCIENCE CHINAChemistry

Yang et al Sci China Chem December (2017) Vol60 No12 1541

of undesirable byproducts (eg Li2CO3) upon cycling thatlead to performance degradation and premature battery death[15] To get rid of this problem completely researchers havereplaced carbon with other noncarbonaceous cathode mate-rials that are inert to these oxidative species Till now somesuitable materials including noble metals [16] RuTiSi2 [17]RuO2NiO [18] RuITO [19] RuSTO [20] metal carbide[21] metal oxides [2223] and transition metal oxidecarboncomposite [24ndash26] have been used in cathodes Despite theseachieved progress the use of these noncarbonaceous cath-odes has some disadvantages All noble metals are expen-sive and difficult to fabricate as a cathode In addition mostmetal oxides used in these carbon-free cathodes suffer fromlow electrical conductivity It is still a daunting challenge todesign a porous carbon-free cathode with low cost high con-ductivity and a good electrochemical performanceWith the above understanding in mind we speculate that

a powerful carbon-free cathode for the Li-O2 battery shouldpossess the following properties (1) a good conductivityfor efficient electron transfer and good activity to promotethe Li-O2 reactions (2) a reasonable structure for fast masstransfer and abundant void space to house the generateddischarge products (3) low cost and ease of fabricationwhich are the premises for the massive practical applicationof these carbon-free cathodes in the Li-O2 battery To thisend we first report the efficient air cathode based on CeO2

nanoparticles (NPs) decorated on NiCo2O4 nanowires ar-rays (NWAs) vertically grown on conductive carbon cloth(CC) First of all the carbon textiles were fully covered byNiCo2O4 NWAs that the influence of carbon substrate couldbe ignored Then highly conductive NiCo2O4 NWAs actas an effective current collector that provides good electrontransport [27] fast mass transfer and sufficient void volumeto house the generated Li2O2 Simultaneously the NiCo2O4

NWAs also possess some oxygen reduction reaction (ORR)activity and oxygen evolution reaction (OER) activity [28]To further improve its activity CeO2 NPs which possessgood ORR and OER activity [2930] are deposited on thesurface of NiCo2O4 NWAs Finally this Li-O2 battery basedon the CeO2NiCo2O4 NWAs-CC (CeNi-CC) cathodedemonstrates the reversible formation and decomposition ofLi2O2 relatively low overpotentials a high specific capacityand high cycle stability due to its unique design in bothstructure and composition

2 Experimental

21 Materials

Urea (99) nickel nitrate hexahydrate (Ni(NO3)26H2O98) cobalt nitrate hexahydrate (Co(NO3)26H2O 99)cerium nitrate hexahydrate (Ce(NO3)36H2O 995) and

hexamethylenetetramine (99) were purchased from Al-addin Reagent (China) Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was the preferred lithium salt forall the experiments reported in this manuscript 1 M LiTFSIin tetraethylene glycol dimethylether (TEGDME) was pre-pared The water content in TEGDME electrolyte measuredby KarlFischer titration is lt 40 ppm

22 Preparation of NiCo2O4 nanowires array

Carbon cloth as a substrate was sequentially cleaned byacetone distilled water and ethanol solution with the as-sistance of sonication for 30 min each In a typical processa transparent pink solution was formed by dissolving028 g of Ni(NO3)26H2O 058 g of Co(NO3)26H2O and0187 g of urea in 35 mL of H2O at room temperature Theobtained solution was transferred into a 40 mL Teflon-linedstainless steel autoclave and put the treated carbon cloth(4 cmtimes4 cm) into it Then the autoclave was heated to120 degC and kept at this temperature for 6 h in a conventionaloven After repeatedly rinsing with distilled water andethanol combined with sonication the product was driedat 80 degC in air Finally the Ni Co-precursor NWAs on thecarbon cloth converted into well crystallized NiCo2O4 NWAsby annealing at 400 degC for 2 h

23 Preparation of CeO2NiCo2O4 nanowires array

One piece carbon cloth (4 cmtimes4 cm) with NiCo2O4 NWAswas first dispersed in a mixture contained 20 mL water and20 mL ethanol Then 2 mL Ce(NO3)3 aqueous solution(01 M) and 3 mL hexamethylenetetramine aqueous solution(HMT 01 M) were added in turn followed by a heatingtreatment at 70 degC for 2 h Then the as-obtained products arewashed with water and ethanol for two times

24 Cell assembly

The electrochemical performance of the Li-O2 cell was testedin a 2025-type coin cell All of the cells were assembled in aglove box under an Ar atmosphere with a lithium metal foilanode a glass fiber separator an oxygen cathode and an elec-trolyte containing 1M LiCF3SO3 in TEGDME The electrodewas cut into a disk with a diameter of 12 mm

25 Instrumentations and characterizations

Powder X-ray diffraction (PXRD) measurements wereperformed on a Rigaku-MiniFlex600 power X-ray diffrac-tometer (Japan) with Cu Kα radiation Scanning electronmicroscope (SEM) was performed on a field emission Hi-tachi S-4800 (Japan) instrument operating at an acceleratingvoltage of 10 kV Samples for SEM were prepared by dis-persing the as-prepared product in ethanol by sonicating for

1542 Yang et al Sci China Chem December (2017) Vol60 No12

around 4 min and then depositing onto an indium tin oxideglass attached to an SEM brass stub Transmission electronmicroscopy (TEM) was performed using an FEI Tecnai G2S-Twin (USA) transmission electron microscope with a fieldemission gun operating at 200 kV Li-O2 cell were tested ona LAND CT2001A (China) multi-channel battery testingsystem

3 Results and discussion

Figure 1(a) shows that the CeO2NiCo2O4 NWAs are grownvertically on the skeletons of the carbon fibers (Figure S1Supporting Information online) forming a free-standing andporous structure As a benefit the problems caused by binderdegradation are avoided since no polymer binder is appliedThe direct growth of active materials on the carbon textileis favorable for electron transportation The void space be-tween these nanowires (Figure 1(b)) offers both sufficientchannels to promote the mass transfer of all reactants andenough room to house the generated Li2O2 being beneficial toimprove the performances of the Li-O2 battery Figure 1(c) re-veals the average diameter of the nanorods is ca 150 nm andthe CeO2 NPs are uniformly distributed along the surfaceof NiCo2O4 NWAs The high-resolution TEM image col-lected at the surface of the NiCo2O4 NWAs (Figure 1(d))reveals lattice fringes of sim031 nm in the (111) plane andsim027 nm in the (200) plane demonstrating the formation ofCeO2 nanoparticles on the NiCo2O4 NWAs Energy-disper-

Figure 1 (a) SEM image of CeO2NiCo2O4 NWAs (b) higher-magnifica-tion of (a) (c) TEM image of CeO2NiCo2O4 NWAs (d) higher magnifica-tion of (c) (e) EDX-mapping analyses of CeO2NiCo2O4 NWAs (f) XRDdata of the as-obtained NiCo2O4 NWAs and CeO2NiCo2O4 NWAs (coloronline)

sive X-ray spectrometry (EDXS) characterization(Figure 1(e)) further reveals the existence and homogeneousdistribution of the CeO2 NPs decorated on the surfaceof NiCo2O4 NWAs indicating that the CeO2NiCo2O4

cathode has been well synthesized in agreement with theXRD results The PXRD analysis (Figure 1(f)) reveals thatthe diffraction peaks can be indexed to well-crystallizedNiCo2O4 (PDF No 20-0781) and CeO2 (PDF No 34-0394)The electrochemical performances of Li-O2 cells with

CeNi-CC and NiCo2O4 NWAs-CC (Ni-CC) cathodesare displayed in Figure 2 To investigate the effect ofCeNi-CC and Ni-CC on the ORR and OER kinetics thefirst discharge-charge curves of the Li-O2 batteries withCeNi-CC and Ni-CC cathodes with the same currentdensity (200 mA gminus1) are obtained which are shown inFigure 2(a) Encouragingly the charge overpotential ofthe battery with CeNi-CC cathode is much lower thanthat of the battery with Ni-CC by about 630 mV showinga much more facile Li2O2 decomposition This excellentOER performance can be attributed to a series of uniquecharacteristics the added CeO2 NPs could effectively im-prove the catalyst kinetics of the cathode [30] the uniquemorphology of the discharge product formed on the cathodeprovides sufficient electrolyte-Li2O2 interfaces that promotethe decomposition of Li2O2 during charge (vide infra)Simultaneously as revealed in Figure 2(a) the dischargeplateau of the battery with the CeNi-CC cathode is higherthan that of battery with the Ni-CC cathode by about 80mV This can be explained by the improved ORR activitythanks to CeO2 deposition [3132] This ORR improvementagrees with the rate performance investigations whichshow that the discharge voltage plateau of the CeNi-CCcathode is higher than that of Ni-CC at each current density(Figure 2(b)) Furthermore the CeNi-CC cathode alsodemonstrates a much larger discharge capacity than theNi-CC cathode at the same current density (Figure 2(cd)) In light of previous report [3334] this improvementin discharge capacity can be explained by the formation ofnanosheet-like Li2O2 on the CeNi-CC cathode rather thanthe muddy Li2O2 formed on the Ni-CC cathode At the sametime to exclude possible electrochemical contributions fromthe intercalation of lithium ions (Li+) into CeNi-CC andNi-CC materials the initial discharge curves of Li-O2 cellswith CeNi-CC and Ni-CC cathodes under an argon (Ar)atmosphere were also obtained for comparison (Figure S2)Clearly the background discharge capacity is negligiblewithin the voltage range which suggests that the aboveobtained enhanced discharge capacities of the Li-O2 cells arederived from the oxygen reductionEncouraged by the good performances achieved by

CeNi-CC cathode we also investigate the cycling perfor-mance of the Li-O2 batteries with these two cathodes shownin Figure 3(andashc) the batteries were tested by controlling the

Yang et al Sci China Chem December (2017) Vol60 No12 1543

Figure 2 (a) First discharge-charge curves of Li-O2 battery with two different cathodes (CeNi-CC and Ni-CC respectively) at a fixed capacity of500 mA h gminus1 (b) the rate capability of the Li-O2 battery with the two types of cathodes at different current densities (c) rate performance of the battery withNi-CC (d) rate performance of the battery with CeNi-CC (color online)

Figure 3 Cycling performance of the battery based on (a) CeNi-CC cathode and (b) Ni-CC cathode with the capacity limited to 500 mA h gminus1 (c) variationof voltage on the terminal discharge of the Li-O2 battery with CeNi-CC (red) Ni-CC (blue) and CC (black) cathode respectively (color online)

discharge depth to 500 mA h gminus1 at a current density of100 mA gminus1 Figure 3(a b) shows the discharge-chargecurves of these batteries based on CeNi-CC and Ni-CC

Their corresponding cutoff voltages are given in Figure 3(c)As revealed the battery with the CeNi-CC cathode candischargecharge for 64 cycles with a discharge terminal

1544 Yang et al Sci China Chem December (2017) Vol60 No12

Figure 4 SEM images of the (a) CeNi-CC and (b) Ni-CC cathode on first discharge respectively (c) SEM images of the CeNi-CC cathode afterrecharge These insets in the panels are the corresponding higher-magnification images (d) GITT discharge voltage profile obtained from the Li-O2 bat-tery with CeNi-CC cathode (color online)

voltage 20 V which is much longer than the cell with theNi-CC cathode that is 34 cyclesTo understand the electrochemistry taking place in the

Li-O2 battery with CeNi-CC cathode and Ni-CC cathodethe morphology of these discharged and charged cathodeswere then investigated Figure 4(a b) shows the first dis-charged morphologies of CeNi-CC cathode Unlike themuddy discharge product formed on the Ni-CC cathode(Figure 4(b)) the discharge products formed on this cath-ode are nanosheets that uniformly grow vertically onto theCeNi-CC cathode indicating the formation of Li2O2 ac-cording to previous reports [34] Compared with the surfaceof pure Ni-CC cathode that of the CeNi-CC cathode isexpected to be less ldquostickyrdquo which can weaken the bindingof the generated superoxide to the substrate thus enhancingthe diffusion of the superoxide molecules away from thecathode surface into the electrolyte As a benefit the solutiongrowth of Li2O2 is promoted leading to nanosheet-shapedstructure growth [34] The uniformly and loosely distributednanosheets provide sufficient product-electrolyte interfaceswhich can promote subsequent charge process and finally en-hance the electrochemical performance of the Li-O2 batteryAfter recharging the discharge product Li2O2 disappears andthe surface of the CeNi-CC cathode becomes clean againrevealing a good rechargeability of this cathode (Figure 4(c))For further understanding the electrochemical behavior inthe Li-O2 battery the galvanostatic intermittent titration tech-nique (GITT) is also applied (Figure 4(d)) The equilibriumpotential of the Li-O2 battery is near 29 V regardless ofthe state of discharge demonstrating the formation of Li2O2

[3536]

4 ConclusionsIn summary a conductive noncarbon and binder-free cath-ode with CeO2 NPs decorated on NiCo2O4 NWAs grownon the CCs is successfully constructed When it is directlyemployed as an O2 cathode the Li-O2 battery shows muchreduced overpotentials high discharge capacity and en-hanced cycling capability The excellent electrochemicalperformance of this battery is ascribed to the reasonable 3Dair cathode structure design and the homogeneous distribu-tion of CeO2 NPs modified on the NiCo2O4 NWAs whichhas tailored the morphology of the discharged product andincreased the ORR as well as OER activity The resultssuggest that both the material and structure of the cathodeshould be optimized to achieve a Li-O2 battery with highelectrochemical performances and provide guidance forfurther cathode design

Acknowledgments This work was supported by the Ministry of Scienceand Technology of the Peoplersquos Republic of China (2017YFA02067042016YFB0100103) the National Basic Research Program of China(2014CB932300) Strategic Priority Research Program of the ChineseAcademy of Sciences (XDA09010404) Technology and Industry forNational Defence of the Peoplersquos Republic of China (JCKY2016130B010)the National Natural Science Foundation of China (51771177 2142210851472232) and Jilin Province Science and Technology DevelopmentProgram (20160101289JC)

Conflict of interest The authors declare that they have no conflict ofinterest

Yang et al Sci China Chem December (2017) Vol60 No12 1545

Supporting information The supporting information is available onlineat httpchemscichinacom and httplinkspringercomjournal11426The supporting materials are published as submitted without typesettingor editing The responsibility for scientific accuracy and content remainsentirely with the authors

1 Gao X Chen Y Johnson L Bruce PG Nat Mater 2016 15 882ndash8882 Lu J Jung Lee Y Luo X Chun Lau K Asadi MWang HH Brombosz

S Wen J Zhai D Chen Z Miller DJ Sub Jeong Y Park JB Zak FangZ Kumar B Salehi-Khojin A Sun YK Curtiss LA Amine KNature2016 529 377ndash382

3 Jung HG Hassoun J Park JB Sun YK Scrosati B Nat Chem 20124 579ndash585

4 Johnson L Li C Liu Z Chen Y Freunberger SA Ashok PC PraveenBB Dholakia K Tarascon JM Bruce PG Nat Chem 2014 61091ndash1099

5 Liu T Leskes M YuW Moore AJ Zhou L Bayley PM Kim G GreyCP Science 2015 350 530ndash533

6 Oh SH Black R Pomerantseva E Lee JH Nazar LFNat Chem 20124 1004ndash1010

7 Ogasawara T Deacutebart A HolzapfelM Novaacutek P Bruce PG J AmChemSoc 2006 128 1390ndash1393

8 Xu JJ Wang ZL Xu D Meng FZ Zhang XB Energ Environ Sci2014 7 2213ndash2219

9 Oh D Qi J Lu YC Zhang Y Shao-Horn Y Belcher AM NatCommun 2013 4 2756

10 Chang Z Xu J Liu Q Li L Zhang X Adv Energ Mater 2015 51500633

11 Xu JJ Xu D Wang ZL Wang HG Zhang LL Zhang XB AngewChem Int Ed 2013 52 3887ndash3890

12 Liao K Wang X Sun Y Tang D Han M He P Jiang X Zhang TZhou H Energ Environ Sci 2015 8 1992ndash1997

13 Lim HD Park KY Song H Jang EY Gwon H Kim J Kim YH LimaMD Ovalle Robles R Leproacute X Baughman RH Kang K Adv Mater2013 25 1348ndash1352

14 Sun B Chen S Liu H Wang G Adv Funct Mater 2015 254436ndash4444

15 Zhang T Zhou H Angew Chem Int Ed 2012 51 11062ndash1106716 Peng Z Freunberger SA Chen Y Bruce PG Science 2012 337

563ndash56617 Xie J Yao X Madden IP Jiang DE Chou LY Tsung CK Wang D J

Am Chem Soc 2014 136 8903ndash890618 Tan P Wei ZH Shyy W Zhao TS Zhu XB Energ Environ Sci 2016

9 1783ndash179319 Li F Tang DM Chen Y Golberg D Kitaura H Zhang T Yamada A

Zhou H Nano Lett 2013 13 4702ndash470720 Li F Tang DM Jian Z Liu D Golberg D Yamada A Zhou H Adv

Mater 2014 26 4659ndash466421 Ottakam Thotiyl MM Freunberger SA Peng Z Chen Y Liu Z Bruce

PG Nat Mater 2013 12 1050ndash105622 ShenCWen ZWang FWuTWuXACSCatal 2016 6 4149ndash415323 Cao J Liu S Xie J Zhang S Cao G Zhao X ACS Catal 2015 5

241ndash24524 Tong S Zheng M Lu Y Lin Z Zhang X He P Zhou H Chem

Commun 2015 51 7302ndash730425 Jiang J He P Tong S Zheng M Lin Z Zhang X Shi Y Zhou H NPG

Asia Mater 2016 8 e23926 Tong S Zheng M Lu Y Lin Z Li J Zhang X Shi Y He P Zhou H J

Mater Chem A 2015 3 16177ndash1618227 Sun B Zhang J Munroe P Ahn HJ Wang G Electrochem Commun

2013 31 88ndash9128 Wang L Zhu T Lyu Z Zhang J Gong L Xiao S Liu J Dong W Cui

X Ho GW Chen W RSC Adv 2016 6 98867ndash9887329 Cao C Xie J Zhang S Pan B Cao G Zhao X J Mater Chem A 2017

5 6747ndash675530 Feng JX Ye SH Xu H Tong YX Li GR Adv Mater 2016 28

4698ndash470331 Lin X Zhou L Huang T Yu A Int J Electrochem Sci 2012 7

9550ndash955932 Kalubarme RS Jadhav HS Park CN Jung KN Shin KH Park CJ J

Mater Chem A 2014 2 13024ndash1303233 Xu JJ Chang ZW Wang Y Liu DP Zhang Y Zhang XB Adv Mater

2016 28 9620ndash962834 Aetukuri NB McCloskey BD Garciacutea JM Krupp LE Viswanathan V

Luntz AC Nat Chem 2015 7 50ndash5635 Lim HK Lim HD Park KY Seo DH Gwon H Hong J Goddard Iii

WA Kim H Kang K J Am Chem Soc 2013 135 9733ndash974236 Cui ZH Guo XX Li H Energ Environ Sci 2015 8 182ndash187

1542 Yang et al Sci China Chem December (2017) Vol60 No12

around 4 min and then depositing onto an indium tin oxideglass attached to an SEM brass stub Transmission electronmicroscopy (TEM) was performed using an FEI Tecnai G2S-Twin (USA) transmission electron microscope with a fieldemission gun operating at 200 kV Li-O2 cell were tested ona LAND CT2001A (China) multi-channel battery testingsystem

3 Results and discussion

Figure 1(a) shows that the CeO2NiCo2O4 NWAs are grownvertically on the skeletons of the carbon fibers (Figure S1Supporting Information online) forming a free-standing andporous structure As a benefit the problems caused by binderdegradation are avoided since no polymer binder is appliedThe direct growth of active materials on the carbon textileis favorable for electron transportation The void space be-tween these nanowires (Figure 1(b)) offers both sufficientchannels to promote the mass transfer of all reactants andenough room to house the generated Li2O2 being beneficial toimprove the performances of the Li-O2 battery Figure 1(c) re-veals the average diameter of the nanorods is ca 150 nm andthe CeO2 NPs are uniformly distributed along the surfaceof NiCo2O4 NWAs The high-resolution TEM image col-lected at the surface of the NiCo2O4 NWAs (Figure 1(d))reveals lattice fringes of sim031 nm in the (111) plane andsim027 nm in the (200) plane demonstrating the formation ofCeO2 nanoparticles on the NiCo2O4 NWAs Energy-disper-

Figure 1 (a) SEM image of CeO2NiCo2O4 NWAs (b) higher-magnifica-tion of (a) (c) TEM image of CeO2NiCo2O4 NWAs (d) higher magnifica-tion of (c) (e) EDX-mapping analyses of CeO2NiCo2O4 NWAs (f) XRDdata of the as-obtained NiCo2O4 NWAs and CeO2NiCo2O4 NWAs (coloronline)

sive X-ray spectrometry (EDXS) characterization(Figure 1(e)) further reveals the existence and homogeneousdistribution of the CeO2 NPs decorated on the surfaceof NiCo2O4 NWAs indicating that the CeO2NiCo2O4

cathode has been well synthesized in agreement with theXRD results The PXRD analysis (Figure 1(f)) reveals thatthe diffraction peaks can be indexed to well-crystallizedNiCo2O4 (PDF No 20-0781) and CeO2 (PDF No 34-0394)The electrochemical performances of Li-O2 cells with

CeNi-CC and NiCo2O4 NWAs-CC (Ni-CC) cathodesare displayed in Figure 2 To investigate the effect ofCeNi-CC and Ni-CC on the ORR and OER kinetics thefirst discharge-charge curves of the Li-O2 batteries withCeNi-CC and Ni-CC cathodes with the same currentdensity (200 mA gminus1) are obtained which are shown inFigure 2(a) Encouragingly the charge overpotential ofthe battery with CeNi-CC cathode is much lower thanthat of the battery with Ni-CC by about 630 mV showinga much more facile Li2O2 decomposition This excellentOER performance can be attributed to a series of uniquecharacteristics the added CeO2 NPs could effectively im-prove the catalyst kinetics of the cathode [30] the uniquemorphology of the discharge product formed on the cathodeprovides sufficient electrolyte-Li2O2 interfaces that promotethe decomposition of Li2O2 during charge (vide infra)Simultaneously as revealed in Figure 2(a) the dischargeplateau of the battery with the CeNi-CC cathode is higherthan that of battery with the Ni-CC cathode by about 80mV This can be explained by the improved ORR activitythanks to CeO2 deposition [3132] This ORR improvementagrees with the rate performance investigations whichshow that the discharge voltage plateau of the CeNi-CCcathode is higher than that of Ni-CC at each current density(Figure 2(b)) Furthermore the CeNi-CC cathode alsodemonstrates a much larger discharge capacity than theNi-CC cathode at the same current density (Figure 2(cd)) In light of previous report [3334] this improvementin discharge capacity can be explained by the formation ofnanosheet-like Li2O2 on the CeNi-CC cathode rather thanthe muddy Li2O2 formed on the Ni-CC cathode At the sametime to exclude possible electrochemical contributions fromthe intercalation of lithium ions (Li+) into CeNi-CC andNi-CC materials the initial discharge curves of Li-O2 cellswith CeNi-CC and Ni-CC cathodes under an argon (Ar)atmosphere were also obtained for comparison (Figure S2)Clearly the background discharge capacity is negligiblewithin the voltage range which suggests that the aboveobtained enhanced discharge capacities of the Li-O2 cells arederived from the oxygen reductionEncouraged by the good performances achieved by

CeNi-CC cathode we also investigate the cycling perfor-mance of the Li-O2 batteries with these two cathodes shownin Figure 3(andashc) the batteries were tested by controlling the

Yang et al Sci China Chem December (2017) Vol60 No12 1543

Figure 2 (a) First discharge-charge curves of Li-O2 battery with two different cathodes (CeNi-CC and Ni-CC respectively) at a fixed capacity of500 mA h gminus1 (b) the rate capability of the Li-O2 battery with the two types of cathodes at different current densities (c) rate performance of the battery withNi-CC (d) rate performance of the battery with CeNi-CC (color online)

Figure 3 Cycling performance of the battery based on (a) CeNi-CC cathode and (b) Ni-CC cathode with the capacity limited to 500 mA h gminus1 (c) variationof voltage on the terminal discharge of the Li-O2 battery with CeNi-CC (red) Ni-CC (blue) and CC (black) cathode respectively (color online)

discharge depth to 500 mA h gminus1 at a current density of100 mA gminus1 Figure 3(a b) shows the discharge-chargecurves of these batteries based on CeNi-CC and Ni-CC

Their corresponding cutoff voltages are given in Figure 3(c)As revealed the battery with the CeNi-CC cathode candischargecharge for 64 cycles with a discharge terminal

1544 Yang et al Sci China Chem December (2017) Vol60 No12

Figure 4 SEM images of the (a) CeNi-CC and (b) Ni-CC cathode on first discharge respectively (c) SEM images of the CeNi-CC cathode afterrecharge These insets in the panels are the corresponding higher-magnification images (d) GITT discharge voltage profile obtained from the Li-O2 bat-tery with CeNi-CC cathode (color online)

voltage 20 V which is much longer than the cell with theNi-CC cathode that is 34 cyclesTo understand the electrochemistry taking place in the

Li-O2 battery with CeNi-CC cathode and Ni-CC cathodethe morphology of these discharged and charged cathodeswere then investigated Figure 4(a b) shows the first dis-charged morphologies of CeNi-CC cathode Unlike themuddy discharge product formed on the Ni-CC cathode(Figure 4(b)) the discharge products formed on this cath-ode are nanosheets that uniformly grow vertically onto theCeNi-CC cathode indicating the formation of Li2O2 ac-cording to previous reports [34] Compared with the surfaceof pure Ni-CC cathode that of the CeNi-CC cathode isexpected to be less ldquostickyrdquo which can weaken the bindingof the generated superoxide to the substrate thus enhancingthe diffusion of the superoxide molecules away from thecathode surface into the electrolyte As a benefit the solutiongrowth of Li2O2 is promoted leading to nanosheet-shapedstructure growth [34] The uniformly and loosely distributednanosheets provide sufficient product-electrolyte interfaceswhich can promote subsequent charge process and finally en-hance the electrochemical performance of the Li-O2 batteryAfter recharging the discharge product Li2O2 disappears andthe surface of the CeNi-CC cathode becomes clean againrevealing a good rechargeability of this cathode (Figure 4(c))For further understanding the electrochemical behavior inthe Li-O2 battery the galvanostatic intermittent titration tech-nique (GITT) is also applied (Figure 4(d)) The equilibriumpotential of the Li-O2 battery is near 29 V regardless ofthe state of discharge demonstrating the formation of Li2O2

[3536]

4 ConclusionsIn summary a conductive noncarbon and binder-free cath-ode with CeO2 NPs decorated on NiCo2O4 NWAs grownon the CCs is successfully constructed When it is directlyemployed as an O2 cathode the Li-O2 battery shows muchreduced overpotentials high discharge capacity and en-hanced cycling capability The excellent electrochemicalperformance of this battery is ascribed to the reasonable 3Dair cathode structure design and the homogeneous distribu-tion of CeO2 NPs modified on the NiCo2O4 NWAs whichhas tailored the morphology of the discharged product andincreased the ORR as well as OER activity The resultssuggest that both the material and structure of the cathodeshould be optimized to achieve a Li-O2 battery with highelectrochemical performances and provide guidance forfurther cathode design

Acknowledgments This work was supported by the Ministry of Scienceand Technology of the Peoplersquos Republic of China (2017YFA02067042016YFB0100103) the National Basic Research Program of China(2014CB932300) Strategic Priority Research Program of the ChineseAcademy of Sciences (XDA09010404) Technology and Industry forNational Defence of the Peoplersquos Republic of China (JCKY2016130B010)the National Natural Science Foundation of China (51771177 2142210851472232) and Jilin Province Science and Technology DevelopmentProgram (20160101289JC)

Conflict of interest The authors declare that they have no conflict ofinterest

Yang et al Sci China Chem December (2017) Vol60 No12 1545

Supporting information The supporting information is available onlineat httpchemscichinacom and httplinkspringercomjournal11426The supporting materials are published as submitted without typesettingor editing The responsibility for scientific accuracy and content remainsentirely with the authors

1 Gao X Chen Y Johnson L Bruce PG Nat Mater 2016 15 882ndash8882 Lu J Jung Lee Y Luo X Chun Lau K Asadi MWang HH Brombosz

S Wen J Zhai D Chen Z Miller DJ Sub Jeong Y Park JB Zak FangZ Kumar B Salehi-Khojin A Sun YK Curtiss LA Amine KNature2016 529 377ndash382

3 Jung HG Hassoun J Park JB Sun YK Scrosati B Nat Chem 20124 579ndash585

4 Johnson L Li C Liu Z Chen Y Freunberger SA Ashok PC PraveenBB Dholakia K Tarascon JM Bruce PG Nat Chem 2014 61091ndash1099

5 Liu T Leskes M YuW Moore AJ Zhou L Bayley PM Kim G GreyCP Science 2015 350 530ndash533

6 Oh SH Black R Pomerantseva E Lee JH Nazar LFNat Chem 20124 1004ndash1010

7 Ogasawara T Deacutebart A HolzapfelM Novaacutek P Bruce PG J AmChemSoc 2006 128 1390ndash1393

8 Xu JJ Wang ZL Xu D Meng FZ Zhang XB Energ Environ Sci2014 7 2213ndash2219

9 Oh D Qi J Lu YC Zhang Y Shao-Horn Y Belcher AM NatCommun 2013 4 2756

10 Chang Z Xu J Liu Q Li L Zhang X Adv Energ Mater 2015 51500633

11 Xu JJ Xu D Wang ZL Wang HG Zhang LL Zhang XB AngewChem Int Ed 2013 52 3887ndash3890

12 Liao K Wang X Sun Y Tang D Han M He P Jiang X Zhang TZhou H Energ Environ Sci 2015 8 1992ndash1997

13 Lim HD Park KY Song H Jang EY Gwon H Kim J Kim YH LimaMD Ovalle Robles R Leproacute X Baughman RH Kang K Adv Mater2013 25 1348ndash1352

14 Sun B Chen S Liu H Wang G Adv Funct Mater 2015 254436ndash4444

15 Zhang T Zhou H Angew Chem Int Ed 2012 51 11062ndash1106716 Peng Z Freunberger SA Chen Y Bruce PG Science 2012 337

563ndash56617 Xie J Yao X Madden IP Jiang DE Chou LY Tsung CK Wang D J

Am Chem Soc 2014 136 8903ndash890618 Tan P Wei ZH Shyy W Zhao TS Zhu XB Energ Environ Sci 2016

9 1783ndash179319 Li F Tang DM Chen Y Golberg D Kitaura H Zhang T Yamada A

Zhou H Nano Lett 2013 13 4702ndash470720 Li F Tang DM Jian Z Liu D Golberg D Yamada A Zhou H Adv

Mater 2014 26 4659ndash466421 Ottakam Thotiyl MM Freunberger SA Peng Z Chen Y Liu Z Bruce

PG Nat Mater 2013 12 1050ndash105622 ShenCWen ZWang FWuTWuXACSCatal 2016 6 4149ndash415323 Cao J Liu S Xie J Zhang S Cao G Zhao X ACS Catal 2015 5

241ndash24524 Tong S Zheng M Lu Y Lin Z Zhang X He P Zhou H Chem

Commun 2015 51 7302ndash730425 Jiang J He P Tong S Zheng M Lin Z Zhang X Shi Y Zhou H NPG

Asia Mater 2016 8 e23926 Tong S Zheng M Lu Y Lin Z Li J Zhang X Shi Y He P Zhou H J

Mater Chem A 2015 3 16177ndash1618227 Sun B Zhang J Munroe P Ahn HJ Wang G Electrochem Commun

2013 31 88ndash9128 Wang L Zhu T Lyu Z Zhang J Gong L Xiao S Liu J Dong W Cui

X Ho GW Chen W RSC Adv 2016 6 98867ndash9887329 Cao C Xie J Zhang S Pan B Cao G Zhao X J Mater Chem A 2017

5 6747ndash675530 Feng JX Ye SH Xu H Tong YX Li GR Adv Mater 2016 28

4698ndash470331 Lin X Zhou L Huang T Yu A Int J Electrochem Sci 2012 7

9550ndash955932 Kalubarme RS Jadhav HS Park CN Jung KN Shin KH Park CJ J

Mater Chem A 2014 2 13024ndash1303233 Xu JJ Chang ZW Wang Y Liu DP Zhang Y Zhang XB Adv Mater

2016 28 9620ndash962834 Aetukuri NB McCloskey BD Garciacutea JM Krupp LE Viswanathan V

Luntz AC Nat Chem 2015 7 50ndash5635 Lim HK Lim HD Park KY Seo DH Gwon H Hong J Goddard Iii

WA Kim H Kang K J Am Chem Soc 2013 135 9733ndash974236 Cui ZH Guo XX Li H Energ Environ Sci 2015 8 182ndash187

Yang et al Sci China Chem December (2017) Vol60 No12 1543

Figure 2 (a) First discharge-charge curves of Li-O2 battery with two different cathodes (CeNi-CC and Ni-CC respectively) at a fixed capacity of500 mA h gminus1 (b) the rate capability of the Li-O2 battery with the two types of cathodes at different current densities (c) rate performance of the battery withNi-CC (d) rate performance of the battery with CeNi-CC (color online)

Figure 3 Cycling performance of the battery based on (a) CeNi-CC cathode and (b) Ni-CC cathode with the capacity limited to 500 mA h gminus1 (c) variationof voltage on the terminal discharge of the Li-O2 battery with CeNi-CC (red) Ni-CC (blue) and CC (black) cathode respectively (color online)

discharge depth to 500 mA h gminus1 at a current density of100 mA gminus1 Figure 3(a b) shows the discharge-chargecurves of these batteries based on CeNi-CC and Ni-CC

Their corresponding cutoff voltages are given in Figure 3(c)As revealed the battery with the CeNi-CC cathode candischargecharge for 64 cycles with a discharge terminal

1544 Yang et al Sci China Chem December (2017) Vol60 No12

Figure 4 SEM images of the (a) CeNi-CC and (b) Ni-CC cathode on first discharge respectively (c) SEM images of the CeNi-CC cathode afterrecharge These insets in the panels are the corresponding higher-magnification images (d) GITT discharge voltage profile obtained from the Li-O2 bat-tery with CeNi-CC cathode (color online)

voltage 20 V which is much longer than the cell with theNi-CC cathode that is 34 cyclesTo understand the electrochemistry taking place in the

Li-O2 battery with CeNi-CC cathode and Ni-CC cathodethe morphology of these discharged and charged cathodeswere then investigated Figure 4(a b) shows the first dis-charged morphologies of CeNi-CC cathode Unlike themuddy discharge product formed on the Ni-CC cathode(Figure 4(b)) the discharge products formed on this cath-ode are nanosheets that uniformly grow vertically onto theCeNi-CC cathode indicating the formation of Li2O2 ac-cording to previous reports [34] Compared with the surfaceof pure Ni-CC cathode that of the CeNi-CC cathode isexpected to be less ldquostickyrdquo which can weaken the bindingof the generated superoxide to the substrate thus enhancingthe diffusion of the superoxide molecules away from thecathode surface into the electrolyte As a benefit the solutiongrowth of Li2O2 is promoted leading to nanosheet-shapedstructure growth [34] The uniformly and loosely distributednanosheets provide sufficient product-electrolyte interfaceswhich can promote subsequent charge process and finally en-hance the electrochemical performance of the Li-O2 batteryAfter recharging the discharge product Li2O2 disappears andthe surface of the CeNi-CC cathode becomes clean againrevealing a good rechargeability of this cathode (Figure 4(c))For further understanding the electrochemical behavior inthe Li-O2 battery the galvanostatic intermittent titration tech-nique (GITT) is also applied (Figure 4(d)) The equilibriumpotential of the Li-O2 battery is near 29 V regardless ofthe state of discharge demonstrating the formation of Li2O2

[3536]

4 ConclusionsIn summary a conductive noncarbon and binder-free cath-ode with CeO2 NPs decorated on NiCo2O4 NWAs grownon the CCs is successfully constructed When it is directlyemployed as an O2 cathode the Li-O2 battery shows muchreduced overpotentials high discharge capacity and en-hanced cycling capability The excellent electrochemicalperformance of this battery is ascribed to the reasonable 3Dair cathode structure design and the homogeneous distribu-tion of CeO2 NPs modified on the NiCo2O4 NWAs whichhas tailored the morphology of the discharged product andincreased the ORR as well as OER activity The resultssuggest that both the material and structure of the cathodeshould be optimized to achieve a Li-O2 battery with highelectrochemical performances and provide guidance forfurther cathode design

Acknowledgments This work was supported by the Ministry of Scienceand Technology of the Peoplersquos Republic of China (2017YFA02067042016YFB0100103) the National Basic Research Program of China(2014CB932300) Strategic Priority Research Program of the ChineseAcademy of Sciences (XDA09010404) Technology and Industry forNational Defence of the Peoplersquos Republic of China (JCKY2016130B010)the National Natural Science Foundation of China (51771177 2142210851472232) and Jilin Province Science and Technology DevelopmentProgram (20160101289JC)

Conflict of interest The authors declare that they have no conflict ofinterest

Yang et al Sci China Chem December (2017) Vol60 No12 1545

Supporting information The supporting information is available onlineat httpchemscichinacom and httplinkspringercomjournal11426The supporting materials are published as submitted without typesettingor editing The responsibility for scientific accuracy and content remainsentirely with the authors

1 Gao X Chen Y Johnson L Bruce PG Nat Mater 2016 15 882ndash8882 Lu J Jung Lee Y Luo X Chun Lau K Asadi MWang HH Brombosz

S Wen J Zhai D Chen Z Miller DJ Sub Jeong Y Park JB Zak FangZ Kumar B Salehi-Khojin A Sun YK Curtiss LA Amine KNature2016 529 377ndash382

3 Jung HG Hassoun J Park JB Sun YK Scrosati B Nat Chem 20124 579ndash585

4 Johnson L Li C Liu Z Chen Y Freunberger SA Ashok PC PraveenBB Dholakia K Tarascon JM Bruce PG Nat Chem 2014 61091ndash1099

5 Liu T Leskes M YuW Moore AJ Zhou L Bayley PM Kim G GreyCP Science 2015 350 530ndash533

6 Oh SH Black R Pomerantseva E Lee JH Nazar LFNat Chem 20124 1004ndash1010

7 Ogasawara T Deacutebart A HolzapfelM Novaacutek P Bruce PG J AmChemSoc 2006 128 1390ndash1393

8 Xu JJ Wang ZL Xu D Meng FZ Zhang XB Energ Environ Sci2014 7 2213ndash2219

9 Oh D Qi J Lu YC Zhang Y Shao-Horn Y Belcher AM NatCommun 2013 4 2756

10 Chang Z Xu J Liu Q Li L Zhang X Adv Energ Mater 2015 51500633

11 Xu JJ Xu D Wang ZL Wang HG Zhang LL Zhang XB AngewChem Int Ed 2013 52 3887ndash3890

12 Liao K Wang X Sun Y Tang D Han M He P Jiang X Zhang TZhou H Energ Environ Sci 2015 8 1992ndash1997

13 Lim HD Park KY Song H Jang EY Gwon H Kim J Kim YH LimaMD Ovalle Robles R Leproacute X Baughman RH Kang K Adv Mater2013 25 1348ndash1352

14 Sun B Chen S Liu H Wang G Adv Funct Mater 2015 254436ndash4444

15 Zhang T Zhou H Angew Chem Int Ed 2012 51 11062ndash1106716 Peng Z Freunberger SA Chen Y Bruce PG Science 2012 337

563ndash56617 Xie J Yao X Madden IP Jiang DE Chou LY Tsung CK Wang D J

Am Chem Soc 2014 136 8903ndash890618 Tan P Wei ZH Shyy W Zhao TS Zhu XB Energ Environ Sci 2016

9 1783ndash179319 Li F Tang DM Chen Y Golberg D Kitaura H Zhang T Yamada A

Zhou H Nano Lett 2013 13 4702ndash470720 Li F Tang DM Jian Z Liu D Golberg D Yamada A Zhou H Adv

Mater 2014 26 4659ndash466421 Ottakam Thotiyl MM Freunberger SA Peng Z Chen Y Liu Z Bruce

PG Nat Mater 2013 12 1050ndash105622 ShenCWen ZWang FWuTWuXACSCatal 2016 6 4149ndash415323 Cao J Liu S Xie J Zhang S Cao G Zhao X ACS Catal 2015 5

241ndash24524 Tong S Zheng M Lu Y Lin Z Zhang X He P Zhou H Chem

Commun 2015 51 7302ndash730425 Jiang J He P Tong S Zheng M Lin Z Zhang X Shi Y Zhou H NPG

Asia Mater 2016 8 e23926 Tong S Zheng M Lu Y Lin Z Li J Zhang X Shi Y He P Zhou H J

Mater Chem A 2015 3 16177ndash1618227 Sun B Zhang J Munroe P Ahn HJ Wang G Electrochem Commun

2013 31 88ndash9128 Wang L Zhu T Lyu Z Zhang J Gong L Xiao S Liu J Dong W Cui

X Ho GW Chen W RSC Adv 2016 6 98867ndash9887329 Cao C Xie J Zhang S Pan B Cao G Zhao X J Mater Chem A 2017

5 6747ndash675530 Feng JX Ye SH Xu H Tong YX Li GR Adv Mater 2016 28

4698ndash470331 Lin X Zhou L Huang T Yu A Int J Electrochem Sci 2012 7

9550ndash955932 Kalubarme RS Jadhav HS Park CN Jung KN Shin KH Park CJ J

Mater Chem A 2014 2 13024ndash1303233 Xu JJ Chang ZW Wang Y Liu DP Zhang Y Zhang XB Adv Mater

2016 28 9620ndash962834 Aetukuri NB McCloskey BD Garciacutea JM Krupp LE Viswanathan V

Luntz AC Nat Chem 2015 7 50ndash5635 Lim HK Lim HD Park KY Seo DH Gwon H Hong J Goddard Iii

WA Kim H Kang K J Am Chem Soc 2013 135 9733ndash974236 Cui ZH Guo XX Li H Energ Environ Sci 2015 8 182ndash187

1544 Yang et al Sci China Chem December (2017) Vol60 No12

Figure 4 SEM images of the (a) CeNi-CC and (b) Ni-CC cathode on first discharge respectively (c) SEM images of the CeNi-CC cathode afterrecharge These insets in the panels are the corresponding higher-magnification images (d) GITT discharge voltage profile obtained from the Li-O2 bat-tery with CeNi-CC cathode (color online)

voltage 20 V which is much longer than the cell with theNi-CC cathode that is 34 cyclesTo understand the electrochemistry taking place in the

Li-O2 battery with CeNi-CC cathode and Ni-CC cathodethe morphology of these discharged and charged cathodeswere then investigated Figure 4(a b) shows the first dis-charged morphologies of CeNi-CC cathode Unlike themuddy discharge product formed on the Ni-CC cathode(Figure 4(b)) the discharge products formed on this cath-ode are nanosheets that uniformly grow vertically onto theCeNi-CC cathode indicating the formation of Li2O2 ac-cording to previous reports [34] Compared with the surfaceof pure Ni-CC cathode that of the CeNi-CC cathode isexpected to be less ldquostickyrdquo which can weaken the bindingof the generated superoxide to the substrate thus enhancingthe diffusion of the superoxide molecules away from thecathode surface into the electrolyte As a benefit the solutiongrowth of Li2O2 is promoted leading to nanosheet-shapedstructure growth [34] The uniformly and loosely distributednanosheets provide sufficient product-electrolyte interfaceswhich can promote subsequent charge process and finally en-hance the electrochemical performance of the Li-O2 batteryAfter recharging the discharge product Li2O2 disappears andthe surface of the CeNi-CC cathode becomes clean againrevealing a good rechargeability of this cathode (Figure 4(c))For further understanding the electrochemical behavior inthe Li-O2 battery the galvanostatic intermittent titration tech-nique (GITT) is also applied (Figure 4(d)) The equilibriumpotential of the Li-O2 battery is near 29 V regardless ofthe state of discharge demonstrating the formation of Li2O2

[3536]

4 ConclusionsIn summary a conductive noncarbon and binder-free cath-ode with CeO2 NPs decorated on NiCo2O4 NWAs grownon the CCs is successfully constructed When it is directlyemployed as an O2 cathode the Li-O2 battery shows muchreduced overpotentials high discharge capacity and en-hanced cycling capability The excellent electrochemicalperformance of this battery is ascribed to the reasonable 3Dair cathode structure design and the homogeneous distribu-tion of CeO2 NPs modified on the NiCo2O4 NWAs whichhas tailored the morphology of the discharged product andincreased the ORR as well as OER activity The resultssuggest that both the material and structure of the cathodeshould be optimized to achieve a Li-O2 battery with highelectrochemical performances and provide guidance forfurther cathode design

Acknowledgments This work was supported by the Ministry of Scienceand Technology of the Peoplersquos Republic of China (2017YFA02067042016YFB0100103) the National Basic Research Program of China(2014CB932300) Strategic Priority Research Program of the ChineseAcademy of Sciences (XDA09010404) Technology and Industry forNational Defence of the Peoplersquos Republic of China (JCKY2016130B010)the National Natural Science Foundation of China (51771177 2142210851472232) and Jilin Province Science and Technology DevelopmentProgram (20160101289JC)

Conflict of interest The authors declare that they have no conflict ofinterest

Yang et al Sci China Chem December (2017) Vol60 No12 1545

Supporting information The supporting information is available onlineat httpchemscichinacom and httplinkspringercomjournal11426The supporting materials are published as submitted without typesettingor editing The responsibility for scientific accuracy and content remainsentirely with the authors

1 Gao X Chen Y Johnson L Bruce PG Nat Mater 2016 15 882ndash8882 Lu J Jung Lee Y Luo X Chun Lau K Asadi MWang HH Brombosz

S Wen J Zhai D Chen Z Miller DJ Sub Jeong Y Park JB Zak FangZ Kumar B Salehi-Khojin A Sun YK Curtiss LA Amine KNature2016 529 377ndash382

3 Jung HG Hassoun J Park JB Sun YK Scrosati B Nat Chem 20124 579ndash585

4 Johnson L Li C Liu Z Chen Y Freunberger SA Ashok PC PraveenBB Dholakia K Tarascon JM Bruce PG Nat Chem 2014 61091ndash1099

5 Liu T Leskes M YuW Moore AJ Zhou L Bayley PM Kim G GreyCP Science 2015 350 530ndash533

6 Oh SH Black R Pomerantseva E Lee JH Nazar LFNat Chem 20124 1004ndash1010

7 Ogasawara T Deacutebart A HolzapfelM Novaacutek P Bruce PG J AmChemSoc 2006 128 1390ndash1393

8 Xu JJ Wang ZL Xu D Meng FZ Zhang XB Energ Environ Sci2014 7 2213ndash2219

9 Oh D Qi J Lu YC Zhang Y Shao-Horn Y Belcher AM NatCommun 2013 4 2756

10 Chang Z Xu J Liu Q Li L Zhang X Adv Energ Mater 2015 51500633

11 Xu JJ Xu D Wang ZL Wang HG Zhang LL Zhang XB AngewChem Int Ed 2013 52 3887ndash3890

12 Liao K Wang X Sun Y Tang D Han M He P Jiang X Zhang TZhou H Energ Environ Sci 2015 8 1992ndash1997

13 Lim HD Park KY Song H Jang EY Gwon H Kim J Kim YH LimaMD Ovalle Robles R Leproacute X Baughman RH Kang K Adv Mater2013 25 1348ndash1352

14 Sun B Chen S Liu H Wang G Adv Funct Mater 2015 254436ndash4444

15 Zhang T Zhou H Angew Chem Int Ed 2012 51 11062ndash1106716 Peng Z Freunberger SA Chen Y Bruce PG Science 2012 337

563ndash56617 Xie J Yao X Madden IP Jiang DE Chou LY Tsung CK Wang D J

Am Chem Soc 2014 136 8903ndash890618 Tan P Wei ZH Shyy W Zhao TS Zhu XB Energ Environ Sci 2016

9 1783ndash179319 Li F Tang DM Chen Y Golberg D Kitaura H Zhang T Yamada A

Zhou H Nano Lett 2013 13 4702ndash470720 Li F Tang DM Jian Z Liu D Golberg D Yamada A Zhou H Adv

Mater 2014 26 4659ndash466421 Ottakam Thotiyl MM Freunberger SA Peng Z Chen Y Liu Z Bruce

PG Nat Mater 2013 12 1050ndash105622 ShenCWen ZWang FWuTWuXACSCatal 2016 6 4149ndash415323 Cao J Liu S Xie J Zhang S Cao G Zhao X ACS Catal 2015 5

241ndash24524 Tong S Zheng M Lu Y Lin Z Zhang X He P Zhou H Chem

Commun 2015 51 7302ndash730425 Jiang J He P Tong S Zheng M Lin Z Zhang X Shi Y Zhou H NPG

Asia Mater 2016 8 e23926 Tong S Zheng M Lu Y Lin Z Li J Zhang X Shi Y He P Zhou H J

Mater Chem A 2015 3 16177ndash1618227 Sun B Zhang J Munroe P Ahn HJ Wang G Electrochem Commun

2013 31 88ndash9128 Wang L Zhu T Lyu Z Zhang J Gong L Xiao S Liu J Dong W Cui

X Ho GW Chen W RSC Adv 2016 6 98867ndash9887329 Cao C Xie J Zhang S Pan B Cao G Zhao X J Mater Chem A 2017

5 6747ndash675530 Feng JX Ye SH Xu H Tong YX Li GR Adv Mater 2016 28

4698ndash470331 Lin X Zhou L Huang T Yu A Int J Electrochem Sci 2012 7

9550ndash955932 Kalubarme RS Jadhav HS Park CN Jung KN Shin KH Park CJ J

Mater Chem A 2014 2 13024ndash1303233 Xu JJ Chang ZW Wang Y Liu DP Zhang Y Zhang XB Adv Mater

2016 28 9620ndash962834 Aetukuri NB McCloskey BD Garciacutea JM Krupp LE Viswanathan V

Luntz AC Nat Chem 2015 7 50ndash5635 Lim HK Lim HD Park KY Seo DH Gwon H Hong J Goddard Iii

WA Kim H Kang K J Am Chem Soc 2013 135 9733ndash974236 Cui ZH Guo XX Li H Energ Environ Sci 2015 8 182ndash187

Yang et al Sci China Chem December (2017) Vol60 No12 1545

Supporting information The supporting information is available onlineat httpchemscichinacom and httplinkspringercomjournal11426The supporting materials are published as submitted without typesettingor editing The responsibility for scientific accuracy and content remainsentirely with the authors

1 Gao X Chen Y Johnson L Bruce PG Nat Mater 2016 15 882ndash8882 Lu J Jung Lee Y Luo X Chun Lau K Asadi MWang HH Brombosz

S Wen J Zhai D Chen Z Miller DJ Sub Jeong Y Park JB Zak FangZ Kumar B Salehi-Khojin A Sun YK Curtiss LA Amine KNature2016 529 377ndash382

3 Jung HG Hassoun J Park JB Sun YK Scrosati B Nat Chem 20124 579ndash585

4 Johnson L Li C Liu Z Chen Y Freunberger SA Ashok PC PraveenBB Dholakia K Tarascon JM Bruce PG Nat Chem 2014 61091ndash1099

5 Liu T Leskes M YuW Moore AJ Zhou L Bayley PM Kim G GreyCP Science 2015 350 530ndash533

6 Oh SH Black R Pomerantseva E Lee JH Nazar LFNat Chem 20124 1004ndash1010

7 Ogasawara T Deacutebart A HolzapfelM Novaacutek P Bruce PG J AmChemSoc 2006 128 1390ndash1393

8 Xu JJ Wang ZL Xu D Meng FZ Zhang XB Energ Environ Sci2014 7 2213ndash2219

9 Oh D Qi J Lu YC Zhang Y Shao-Horn Y Belcher AM NatCommun 2013 4 2756

10 Chang Z Xu J Liu Q Li L Zhang X Adv Energ Mater 2015 51500633

11 Xu JJ Xu D Wang ZL Wang HG Zhang LL Zhang XB AngewChem Int Ed 2013 52 3887ndash3890

12 Liao K Wang X Sun Y Tang D Han M He P Jiang X Zhang TZhou H Energ Environ Sci 2015 8 1992ndash1997

13 Lim HD Park KY Song H Jang EY Gwon H Kim J Kim YH LimaMD Ovalle Robles R Leproacute X Baughman RH Kang K Adv Mater2013 25 1348ndash1352

14 Sun B Chen S Liu H Wang G Adv Funct Mater 2015 254436ndash4444

15 Zhang T Zhou H Angew Chem Int Ed 2012 51 11062ndash1106716 Peng Z Freunberger SA Chen Y Bruce PG Science 2012 337

563ndash56617 Xie J Yao X Madden IP Jiang DE Chou LY Tsung CK Wang D J

Am Chem Soc 2014 136 8903ndash890618 Tan P Wei ZH Shyy W Zhao TS Zhu XB Energ Environ Sci 2016

9 1783ndash179319 Li F Tang DM Chen Y Golberg D Kitaura H Zhang T Yamada A

Zhou H Nano Lett 2013 13 4702ndash470720 Li F Tang DM Jian Z Liu D Golberg D Yamada A Zhou H Adv

Mater 2014 26 4659ndash466421 Ottakam Thotiyl MM Freunberger SA Peng Z Chen Y Liu Z Bruce

PG Nat Mater 2013 12 1050ndash105622 ShenCWen ZWang FWuTWuXACSCatal 2016 6 4149ndash415323 Cao J Liu S Xie J Zhang S Cao G Zhao X ACS Catal 2015 5

241ndash24524 Tong S Zheng M Lu Y Lin Z Zhang X He P Zhou H Chem

Commun 2015 51 7302ndash730425 Jiang J He P Tong S Zheng M Lin Z Zhang X Shi Y Zhou H NPG

Asia Mater 2016 8 e23926 Tong S Zheng M Lu Y Lin Z Li J Zhang X Shi Y He P Zhou H J

Mater Chem A 2015 3 16177ndash1618227 Sun B Zhang J Munroe P Ahn HJ Wang G Electrochem Commun

2013 31 88ndash9128 Wang L Zhu T Lyu Z Zhang J Gong L Xiao S Liu J Dong W Cui

X Ho GW Chen W RSC Adv 2016 6 98867ndash9887329 Cao C Xie J Zhang S Pan B Cao G Zhao X J Mater Chem A 2017

5 6747ndash675530 Feng JX Ye SH Xu H Tong YX Li GR Adv Mater 2016 28

4698ndash470331 Lin X Zhou L Huang T Yu A Int J Electrochem Sci 2012 7

9550ndash955932 Kalubarme RS Jadhav HS Park CN Jung KN Shin KH Park CJ J

Mater Chem A 2014 2 13024ndash1303233 Xu JJ Chang ZW Wang Y Liu DP Zhang Y Zhang XB Adv Mater

2016 28 9620ndash962834 Aetukuri NB McCloskey BD Garciacutea JM Krupp LE Viswanathan V

Luntz AC Nat Chem 2015 7 50ndash5635 Lim HK Lim HD Park KY Seo DH Gwon H Hong J Goddard Iii

WA Kim H Kang K J Am Chem Soc 2013 135 9733ndash974236 Cui ZH Guo XX Li H Energ Environ Sci 2015 8 182ndash187