Supporting information

A zinc battery with ultra-flat discharge plateau through phase

transition mechanism

Donghong Wanga Yuwei Zhaoa Guojin Lianga Funian Moa Hongfei Lia Zhaodong

Huanga Xinliang Lia Tiancheng Tanga Binbin Dongb Chunyi Zhiac

a Department of Materials Science and Engineering City University of Hong Kong

83 Tat Chee Avenue Kowloon Hong Kong 999077 China

Email cyzhicityueduhk

b National Engineering Research Center for Advanced Polymer Processing

Technology Zhengzhou University Zhengzhou Henan 450002 China

c Center for Advanced Nuclear Safety and Sustainable Development City University

of Hong Kong Kowloon Hong Kong

1

Fig S1 TEM of the as-prepared Bi2O3

Fig S2 (a) CV curves of Bi2O3 in 6 M KOH + 03M Zn(Ac)2 using Pt plate as the

counter electrode HgOHg as the reference electrode at 05 mV sndash1 (c) CV curves of

Bi2O3 in 6 M KOH + 03M Zn(Ac)2 using Zn plate as the counter and reference

electrode at 1 mV sndash1

The reaction for the tiny oxidation peak is

Bi+4OH‒=BiO2‒+3e‒+2H2O (S1)

2

As the potential for Bi to BiO2‒ is smaller than the potential needed to Bi2O3

[1] it has

the tendency for Bi to be oxidized to BiO2‒ firstly with large amount of OH‒ around

However it will decompose to Bi2O3 as the consuming of OH‒ since only one peak

appears in the reduction process

2BiO2‒+H2O=Bi2O3+2OH‒ (S2)

Fig S3 (a c) Cyclic voltammogram and (b d) coulombic efficiency of Zn

platingstripping in a three-electrode cell using a Cu foil (1cmtimes1cm) as the working

electrode and Zn as the reference and counter electrodes at a scan rate of 2 mV sminus1 (a)

and 10 mV s‒1 (c) and current density of 2 mA cm‒2 (b) and 10 mA cm‒2 (d)

respectively

3

Fig S4 The galvanostatic chargendashdischarge curves at various current density

Fig S5 (a) Cycling stability evaluation at different current densities 1A g‒1 5 A g‒1

10 A g‒1 and 20 A g‒1 Due to a large overpotential at 20 A g‒1 activation was

conducted at 1 A g‒1 for 20 cycles (b) Coulombic efficiencies at 1A g‒1 (c) The

charge-discharge curves of first 11 cycles

Due to the pure phase transition mechanism the main feature is induced by the

structural change It includes breaking of chemical bonds and re-establishing new

4

bonds which results in structural collapse of the original one and is the failure

mechanism As exhibited in the ex-situ XRD patterns in Fig 4a the atoms rearranged

after phase-transition from Bi2O3 to Bi Due to the structural break after each

discharge a small portion of Bi is separated to become invalid and cannot charged

back to Bi2O3 The structural collapse of the original one is responsible for the

degradation

Fig S6 Comparison of the Ragone plot among the Zn-Bi2O3 cell and the other two

reported materials (Na044Mn2O414H2O[2] and V2O5nH2O[3]) for the aqueous Zn

batteries and several other aqueous batteries (Ni-Fe[4] Ni-Bi[5] Bi-Co3O4[6] and Bi2O3-

MnO2 supercapacitor[7])

5

Fig S7 XRD patterns of the discharge product and the corresponding standard pattern

of Bi

Fig S8 Raman spectra of cathodes collected at different discharge-charge stages the

stages are labeled in Fig 4b

6

Fig S9 Evaluation of stability of Bi2O3 cathode after cycled for different cycles The

first two cycles were performed on Bi2O3 cathodes with a content of 90 wt and 5 wt

for Bi2O3 and carbon black respectively while for longer cycles the content of

Bi2O3 is 80 wt with the carbon black of 10 wt

7

Fig S10 Electrochemical performance of Bi2O3 in mild electrolyte (a b) CV curve

and cycle performance in 3 M Zn(CF3SO3)2 with the inset showing the corresponding

charge-discharge curves at the 10th cycle (c d) CV curve and cycle performance in 2

M ZnSO4 with the inset showing the corresponding charge-discharge curves at the

10th cycle (e f) Cycle performance and the 10th charge-discharge curves in 1M KOH

When 3 M Zn(CF3SO3)2 and 2 M ZnSO4 was used as electrolyte obviously the

overpotential largely increased with the discharge voltage shifted to 017 V (Fig

8

S10a) and 045 V (Fig S10c) respectively In addition two-step reaction appeared

instead of the single transition as certificated by the two pairs of redox peaks in the

CV curves Most importantly limited capacity and poor cycle stability was delivered

in the two mild electrolytes as shown in Fig S10b and d In contrast when 1 M KOH

electrolyte is used the activity was boosted as shown in Fig S10e and f the capacity

was lifted to be over 200 mAh gndash1 and the overpotential decreased largely with the

flat plateau appeared However the cycling performance was poor faded to almost 0

after only 20 cycles which cannot compare with that in 6 M KOH+03 M Zn(Ac)2

Other work already reported that Bi2O3 or Bi are reversible in 1 M KOH and 6 M

KOH with the reaction between Bi2O3 and Bi[8-9] Thus the different electrochemical

behaviors of the batteries with different electrolyte can be ascribed to the Zn anode

The rechargeability of zinc batteries is in relation to the anode issues which are

closely affected by the electrolyte nature[10] Large amounts of research work reveal

that in alkaline electrolyte the reversibility and lifetime rely on the concentration of

KOH[10-13] While the increase of KOH concentration decreases the electrode potential

the conductivity and exchange current associated with reaction kinetics increase

reaching a maximum at about 33 (6 M)[12 14-15] Thatrsquos why the overpotential of Zn-

Bi2O3 in 1M KOH is larger than that in 6 M KOH and the lifetime in 6 M KOH is

higher than that in 1 M KOH However another problem arises as the strong alkaline

electrolytes (6 M KOH) cause a high solubility of zinc an effective method to reduce

the solubility is to use additives including Zn(Ac)2[14 16-17] ZnO[12] and KF[12] etc

Therefore Zn-Bi2O3 delivered the best performance in the electrolyte of 6 M KOH

9

and 03 M Zn(Ac)2 among these different electrolytes

Fig S11 (a-c) Electrochemical properties of flexible ZnBi2O3 using sodium

polyacrylate (PANa) hydrogel CV curve of at 02 mV sndash1 (a) discharge-charge

profile at 1 A g-1 capacity versus cycle number at 1 A g-1(c) (d) a picture illustration

of two-connected flexible battery devices powering an electrical watch

References

[1] AM Espinosa MT San Joseacute ML Tascoacuten MD Vaacuteszquez P Saacutenchez Batanero Electrochimica Acta 36 (1991) 1561-1571[2] D Wang L Wang G Liang H Li Z Liu Z Tang J Liang C Zhi ACS Nano 13 (2019) 10643-10652[3] M Yan P He Y Chen S Wang Q Wei K Zhao X Xu Q An Y Shuang Y Shao KT Mueller L Mai J Liu J Yang Advanced Materials 30 (2018) 1703725[4] H Wang Y Liang M Gong Y Li W Chang T Mefford J Zhou J Wang T

10

Regier F Wei H Dai Nature Communications 3 (2012) 917[5] Y Zeng Z Lin Y Meng Y Wang M Yu X Lu Y Tong Advanced Materials 28 (2016) 9188-9195[6] R Liu L Ma G Niu X Li E Li Y Bai G Yuan Advanced Functional Materials 27 (2017) 1701635[7] H Xu X Hu H Yang Y Sun C Hu Y Huang Advanced Energy Materials 5 (2015) 1401882[8] W Fang L Fan Y Zhang Q Zhang Y Yin N Zhang K Sun Ceramics International 43 (2017) 8819-8823[9] SX Wang CC Jin WJ Qian Journal of Alloys and Compounds 615 (2014) 12-17[10]AR Mainar E Iruin LC Colmenares A Kvasha I De Meatza M Bengoechea O Leonet I Boyano Z Zhang JA Blazquez Journal of Energy Storage 15 (2018) 304-328[11] A R Mainar O Leonet M Bengoechea I Boyano I De Meatza A Kvasha A Guerfi J Alberto Blaacutezquez International Journal of Energy Research 40 (2016) 1032-1049[12]R Shivkumar G Paruthimal Kalaignan T Vasudevan Journal of Power Sources 55 (1995) 53-62[13]H Li L Ma C Han Z Wang Z Liu Z Tang C Zhi Nano Energy 62 (2019) 550-587[14]W Shang W Yu P Tan B Chen Z Wu H Xu M Ni Journal of Materials Chemistry A 7 (2019) 15564-15574[15]P Gu M Zheng Q Zhao X Xiao H Xue H Pang Journal of Materials Chemistry A 5 (2017) 7651-7666[16]Y Huang Z Li Z Pei Z Liu H Li M Zhu J Fan Q Dai M Zhang L Dai C Zhi Advanced Energy Materials 8 (2018) 1802288[17]L Ma S Chen D Wang Q Yang F Mo G Liang N Li H Zhang JA Zapien C Zhi Advanced Energy Materials 9 (2019) 1803046

11

As the potential for Bi to BiO2‒ is smaller than the potential needed to Bi2O3

[1] it has

the tendency for Bi to be oxidized to BiO2‒ firstly with large amount of OH‒ around

However it will decompose to Bi2O3 as the consuming of OH‒ since only one peak

appears in the reduction process

2BiO2‒+H2O=Bi2O3+2OH‒ (S2)

Fig S3 (a c) Cyclic voltammogram and (b d) coulombic efficiency of Zn

platingstripping in a three-electrode cell using a Cu foil (1cmtimes1cm) as the working

electrode and Zn as the reference and counter electrodes at a scan rate of 2 mV sminus1 (a)

and 10 mV s‒1 (c) and current density of 2 mA cm‒2 (b) and 10 mA cm‒2 (d)

respectively

3

Fig S4 The galvanostatic chargendashdischarge curves at various current density

Fig S5 (a) Cycling stability evaluation at different current densities 1A g‒1 5 A g‒1

10 A g‒1 and 20 A g‒1 Due to a large overpotential at 20 A g‒1 activation was

conducted at 1 A g‒1 for 20 cycles (b) Coulombic efficiencies at 1A g‒1 (c) The

charge-discharge curves of first 11 cycles

Due to the pure phase transition mechanism the main feature is induced by the

structural change It includes breaking of chemical bonds and re-establishing new

4

bonds which results in structural collapse of the original one and is the failure

mechanism As exhibited in the ex-situ XRD patterns in Fig 4a the atoms rearranged

after phase-transition from Bi2O3 to Bi Due to the structural break after each

discharge a small portion of Bi is separated to become invalid and cannot charged

back to Bi2O3 The structural collapse of the original one is responsible for the

degradation

Fig S6 Comparison of the Ragone plot among the Zn-Bi2O3 cell and the other two

reported materials (Na044Mn2O414H2O[2] and V2O5nH2O[3]) for the aqueous Zn

batteries and several other aqueous batteries (Ni-Fe[4] Ni-Bi[5] Bi-Co3O4[6] and Bi2O3-

MnO2 supercapacitor[7])

5

Fig S7 XRD patterns of the discharge product and the corresponding standard pattern

of Bi

Fig S8 Raman spectra of cathodes collected at different discharge-charge stages the

stages are labeled in Fig 4b

6

Fig S9 Evaluation of stability of Bi2O3 cathode after cycled for different cycles The

first two cycles were performed on Bi2O3 cathodes with a content of 90 wt and 5 wt

for Bi2O3 and carbon black respectively while for longer cycles the content of

Bi2O3 is 80 wt with the carbon black of 10 wt

7

Fig S10 Electrochemical performance of Bi2O3 in mild electrolyte (a b) CV curve

and cycle performance in 3 M Zn(CF3SO3)2 with the inset showing the corresponding

charge-discharge curves at the 10th cycle (c d) CV curve and cycle performance in 2

M ZnSO4 with the inset showing the corresponding charge-discharge curves at the

10th cycle (e f) Cycle performance and the 10th charge-discharge curves in 1M KOH

When 3 M Zn(CF3SO3)2 and 2 M ZnSO4 was used as electrolyte obviously the

overpotential largely increased with the discharge voltage shifted to 017 V (Fig

8

S10a) and 045 V (Fig S10c) respectively In addition two-step reaction appeared

instead of the single transition as certificated by the two pairs of redox peaks in the

CV curves Most importantly limited capacity and poor cycle stability was delivered

in the two mild electrolytes as shown in Fig S10b and d In contrast when 1 M KOH

electrolyte is used the activity was boosted as shown in Fig S10e and f the capacity

was lifted to be over 200 mAh gndash1 and the overpotential decreased largely with the

flat plateau appeared However the cycling performance was poor faded to almost 0

after only 20 cycles which cannot compare with that in 6 M KOH+03 M Zn(Ac)2

Other work already reported that Bi2O3 or Bi are reversible in 1 M KOH and 6 M

KOH with the reaction between Bi2O3 and Bi[8-9] Thus the different electrochemical

behaviors of the batteries with different electrolyte can be ascribed to the Zn anode

The rechargeability of zinc batteries is in relation to the anode issues which are

closely affected by the electrolyte nature[10] Large amounts of research work reveal

that in alkaline electrolyte the reversibility and lifetime rely on the concentration of

KOH[10-13] While the increase of KOH concentration decreases the electrode potential

the conductivity and exchange current associated with reaction kinetics increase

reaching a maximum at about 33 (6 M)[12 14-15] Thatrsquos why the overpotential of Zn-

Bi2O3 in 1M KOH is larger than that in 6 M KOH and the lifetime in 6 M KOH is

higher than that in 1 M KOH However another problem arises as the strong alkaline

electrolytes (6 M KOH) cause a high solubility of zinc an effective method to reduce

the solubility is to use additives including Zn(Ac)2[14 16-17] ZnO[12] and KF[12] etc

Therefore Zn-Bi2O3 delivered the best performance in the electrolyte of 6 M KOH

9

and 03 M Zn(Ac)2 among these different electrolytes

Fig S11 (a-c) Electrochemical properties of flexible ZnBi2O3 using sodium

polyacrylate (PANa) hydrogel CV curve of at 02 mV sndash1 (a) discharge-charge

profile at 1 A g-1 capacity versus cycle number at 1 A g-1(c) (d) a picture illustration

of two-connected flexible battery devices powering an electrical watch

References

[1] AM Espinosa MT San Joseacute ML Tascoacuten MD Vaacuteszquez P Saacutenchez Batanero Electrochimica Acta 36 (1991) 1561-1571[2] D Wang L Wang G Liang H Li Z Liu Z Tang J Liang C Zhi ACS Nano 13 (2019) 10643-10652[3] M Yan P He Y Chen S Wang Q Wei K Zhao X Xu Q An Y Shuang Y Shao KT Mueller L Mai J Liu J Yang Advanced Materials 30 (2018) 1703725[4] H Wang Y Liang M Gong Y Li W Chang T Mefford J Zhou J Wang T

10

Regier F Wei H Dai Nature Communications 3 (2012) 917[5] Y Zeng Z Lin Y Meng Y Wang M Yu X Lu Y Tong Advanced Materials 28 (2016) 9188-9195[6] R Liu L Ma G Niu X Li E Li Y Bai G Yuan Advanced Functional Materials 27 (2017) 1701635[7] H Xu X Hu H Yang Y Sun C Hu Y Huang Advanced Energy Materials 5 (2015) 1401882[8] W Fang L Fan Y Zhang Q Zhang Y Yin N Zhang K Sun Ceramics International 43 (2017) 8819-8823[9] SX Wang CC Jin WJ Qian Journal of Alloys and Compounds 615 (2014) 12-17[10]AR Mainar E Iruin LC Colmenares A Kvasha I De Meatza M Bengoechea O Leonet I Boyano Z Zhang JA Blazquez Journal of Energy Storage 15 (2018) 304-328[11] A R Mainar O Leonet M Bengoechea I Boyano I De Meatza A Kvasha A Guerfi J Alberto Blaacutezquez International Journal of Energy Research 40 (2016) 1032-1049[12]R Shivkumar G Paruthimal Kalaignan T Vasudevan Journal of Power Sources 55 (1995) 53-62[13]H Li L Ma C Han Z Wang Z Liu Z Tang C Zhi Nano Energy 62 (2019) 550-587[14]W Shang W Yu P Tan B Chen Z Wu H Xu M Ni Journal of Materials Chemistry A 7 (2019) 15564-15574[15]P Gu M Zheng Q Zhao X Xiao H Xue H Pang Journal of Materials Chemistry A 5 (2017) 7651-7666[16]Y Huang Z Li Z Pei Z Liu H Li M Zhu J Fan Q Dai M Zhang L Dai C Zhi Advanced Energy Materials 8 (2018) 1802288[17]L Ma S Chen D Wang Q Yang F Mo G Liang N Li H Zhang JA Zapien C Zhi Advanced Energy Materials 9 (2019) 1803046

11

Fig S4 The galvanostatic chargendashdischarge curves at various current density

Fig S5 (a) Cycling stability evaluation at different current densities 1A g‒1 5 A g‒1

10 A g‒1 and 20 A g‒1 Due to a large overpotential at 20 A g‒1 activation was

conducted at 1 A g‒1 for 20 cycles (b) Coulombic efficiencies at 1A g‒1 (c) The

charge-discharge curves of first 11 cycles

Due to the pure phase transition mechanism the main feature is induced by the

structural change It includes breaking of chemical bonds and re-establishing new

4

bonds which results in structural collapse of the original one and is the failure

mechanism As exhibited in the ex-situ XRD patterns in Fig 4a the atoms rearranged

after phase-transition from Bi2O3 to Bi Due to the structural break after each

discharge a small portion of Bi is separated to become invalid and cannot charged

back to Bi2O3 The structural collapse of the original one is responsible for the

degradation

Fig S6 Comparison of the Ragone plot among the Zn-Bi2O3 cell and the other two

reported materials (Na044Mn2O414H2O[2] and V2O5nH2O[3]) for the aqueous Zn

batteries and several other aqueous batteries (Ni-Fe[4] Ni-Bi[5] Bi-Co3O4[6] and Bi2O3-

MnO2 supercapacitor[7])

5

Fig S7 XRD patterns of the discharge product and the corresponding standard pattern

of Bi

Fig S8 Raman spectra of cathodes collected at different discharge-charge stages the

stages are labeled in Fig 4b

6

Fig S9 Evaluation of stability of Bi2O3 cathode after cycled for different cycles The

first two cycles were performed on Bi2O3 cathodes with a content of 90 wt and 5 wt

for Bi2O3 and carbon black respectively while for longer cycles the content of

Bi2O3 is 80 wt with the carbon black of 10 wt

7

Fig S10 Electrochemical performance of Bi2O3 in mild electrolyte (a b) CV curve

and cycle performance in 3 M Zn(CF3SO3)2 with the inset showing the corresponding

charge-discharge curves at the 10th cycle (c d) CV curve and cycle performance in 2

M ZnSO4 with the inset showing the corresponding charge-discharge curves at the

10th cycle (e f) Cycle performance and the 10th charge-discharge curves in 1M KOH

When 3 M Zn(CF3SO3)2 and 2 M ZnSO4 was used as electrolyte obviously the

overpotential largely increased with the discharge voltage shifted to 017 V (Fig

8

S10a) and 045 V (Fig S10c) respectively In addition two-step reaction appeared

instead of the single transition as certificated by the two pairs of redox peaks in the

CV curves Most importantly limited capacity and poor cycle stability was delivered

in the two mild electrolytes as shown in Fig S10b and d In contrast when 1 M KOH

electrolyte is used the activity was boosted as shown in Fig S10e and f the capacity

was lifted to be over 200 mAh gndash1 and the overpotential decreased largely with the

flat plateau appeared However the cycling performance was poor faded to almost 0

after only 20 cycles which cannot compare with that in 6 M KOH+03 M Zn(Ac)2

Other work already reported that Bi2O3 or Bi are reversible in 1 M KOH and 6 M

KOH with the reaction between Bi2O3 and Bi[8-9] Thus the different electrochemical

behaviors of the batteries with different electrolyte can be ascribed to the Zn anode

The rechargeability of zinc batteries is in relation to the anode issues which are

closely affected by the electrolyte nature[10] Large amounts of research work reveal

that in alkaline electrolyte the reversibility and lifetime rely on the concentration of

KOH[10-13] While the increase of KOH concentration decreases the electrode potential

the conductivity and exchange current associated with reaction kinetics increase

reaching a maximum at about 33 (6 M)[12 14-15] Thatrsquos why the overpotential of Zn-

Bi2O3 in 1M KOH is larger than that in 6 M KOH and the lifetime in 6 M KOH is

higher than that in 1 M KOH However another problem arises as the strong alkaline

electrolytes (6 M KOH) cause a high solubility of zinc an effective method to reduce

the solubility is to use additives including Zn(Ac)2[14 16-17] ZnO[12] and KF[12] etc

Therefore Zn-Bi2O3 delivered the best performance in the electrolyte of 6 M KOH

9

and 03 M Zn(Ac)2 among these different electrolytes

Fig S11 (a-c) Electrochemical properties of flexible ZnBi2O3 using sodium

polyacrylate (PANa) hydrogel CV curve of at 02 mV sndash1 (a) discharge-charge

profile at 1 A g-1 capacity versus cycle number at 1 A g-1(c) (d) a picture illustration

of two-connected flexible battery devices powering an electrical watch

References

[1] AM Espinosa MT San Joseacute ML Tascoacuten MD Vaacuteszquez P Saacutenchez Batanero Electrochimica Acta 36 (1991) 1561-1571[2] D Wang L Wang G Liang H Li Z Liu Z Tang J Liang C Zhi ACS Nano 13 (2019) 10643-10652[3] M Yan P He Y Chen S Wang Q Wei K Zhao X Xu Q An Y Shuang Y Shao KT Mueller L Mai J Liu J Yang Advanced Materials 30 (2018) 1703725[4] H Wang Y Liang M Gong Y Li W Chang T Mefford J Zhou J Wang T

10

Regier F Wei H Dai Nature Communications 3 (2012) 917[5] Y Zeng Z Lin Y Meng Y Wang M Yu X Lu Y Tong Advanced Materials 28 (2016) 9188-9195[6] R Liu L Ma G Niu X Li E Li Y Bai G Yuan Advanced Functional Materials 27 (2017) 1701635[7] H Xu X Hu H Yang Y Sun C Hu Y Huang Advanced Energy Materials 5 (2015) 1401882[8] W Fang L Fan Y Zhang Q Zhang Y Yin N Zhang K Sun Ceramics International 43 (2017) 8819-8823[9] SX Wang CC Jin WJ Qian Journal of Alloys and Compounds 615 (2014) 12-17[10]AR Mainar E Iruin LC Colmenares A Kvasha I De Meatza M Bengoechea O Leonet I Boyano Z Zhang JA Blazquez Journal of Energy Storage 15 (2018) 304-328[11] A R Mainar O Leonet M Bengoechea I Boyano I De Meatza A Kvasha A Guerfi J Alberto Blaacutezquez International Journal of Energy Research 40 (2016) 1032-1049[12]R Shivkumar G Paruthimal Kalaignan T Vasudevan Journal of Power Sources 55 (1995) 53-62[13]H Li L Ma C Han Z Wang Z Liu Z Tang C Zhi Nano Energy 62 (2019) 550-587[14]W Shang W Yu P Tan B Chen Z Wu H Xu M Ni Journal of Materials Chemistry A 7 (2019) 15564-15574[15]P Gu M Zheng Q Zhao X Xiao H Xue H Pang Journal of Materials Chemistry A 5 (2017) 7651-7666[16]Y Huang Z Li Z Pei Z Liu H Li M Zhu J Fan Q Dai M Zhang L Dai C Zhi Advanced Energy Materials 8 (2018) 1802288[17]L Ma S Chen D Wang Q Yang F Mo G Liang N Li H Zhang JA Zapien C Zhi Advanced Energy Materials 9 (2019) 1803046

11

bonds which results in structural collapse of the original one and is the failure

mechanism As exhibited in the ex-situ XRD patterns in Fig 4a the atoms rearranged

after phase-transition from Bi2O3 to Bi Due to the structural break after each

discharge a small portion of Bi is separated to become invalid and cannot charged

back to Bi2O3 The structural collapse of the original one is responsible for the

degradation

Fig S6 Comparison of the Ragone plot among the Zn-Bi2O3 cell and the other two

reported materials (Na044Mn2O414H2O[2] and V2O5nH2O[3]) for the aqueous Zn

batteries and several other aqueous batteries (Ni-Fe[4] Ni-Bi[5] Bi-Co3O4[6] and Bi2O3-

MnO2 supercapacitor[7])

5

Fig S7 XRD patterns of the discharge product and the corresponding standard pattern

of Bi

Fig S8 Raman spectra of cathodes collected at different discharge-charge stages the

stages are labeled in Fig 4b

6

Fig S9 Evaluation of stability of Bi2O3 cathode after cycled for different cycles The

first two cycles were performed on Bi2O3 cathodes with a content of 90 wt and 5 wt

for Bi2O3 and carbon black respectively while for longer cycles the content of

Bi2O3 is 80 wt with the carbon black of 10 wt

7

Fig S10 Electrochemical performance of Bi2O3 in mild electrolyte (a b) CV curve

and cycle performance in 3 M Zn(CF3SO3)2 with the inset showing the corresponding

charge-discharge curves at the 10th cycle (c d) CV curve and cycle performance in 2

M ZnSO4 with the inset showing the corresponding charge-discharge curves at the

10th cycle (e f) Cycle performance and the 10th charge-discharge curves in 1M KOH

When 3 M Zn(CF3SO3)2 and 2 M ZnSO4 was used as electrolyte obviously the

overpotential largely increased with the discharge voltage shifted to 017 V (Fig

8

S10a) and 045 V (Fig S10c) respectively In addition two-step reaction appeared

instead of the single transition as certificated by the two pairs of redox peaks in the

CV curves Most importantly limited capacity and poor cycle stability was delivered

in the two mild electrolytes as shown in Fig S10b and d In contrast when 1 M KOH

electrolyte is used the activity was boosted as shown in Fig S10e and f the capacity

was lifted to be over 200 mAh gndash1 and the overpotential decreased largely with the

flat plateau appeared However the cycling performance was poor faded to almost 0

after only 20 cycles which cannot compare with that in 6 M KOH+03 M Zn(Ac)2

Other work already reported that Bi2O3 or Bi are reversible in 1 M KOH and 6 M

KOH with the reaction between Bi2O3 and Bi[8-9] Thus the different electrochemical

behaviors of the batteries with different electrolyte can be ascribed to the Zn anode

The rechargeability of zinc batteries is in relation to the anode issues which are

closely affected by the electrolyte nature[10] Large amounts of research work reveal

that in alkaline electrolyte the reversibility and lifetime rely on the concentration of

KOH[10-13] While the increase of KOH concentration decreases the electrode potential

the conductivity and exchange current associated with reaction kinetics increase

reaching a maximum at about 33 (6 M)[12 14-15] Thatrsquos why the overpotential of Zn-

Bi2O3 in 1M KOH is larger than that in 6 M KOH and the lifetime in 6 M KOH is

higher than that in 1 M KOH However another problem arises as the strong alkaline

electrolytes (6 M KOH) cause a high solubility of zinc an effective method to reduce

the solubility is to use additives including Zn(Ac)2[14 16-17] ZnO[12] and KF[12] etc

Therefore Zn-Bi2O3 delivered the best performance in the electrolyte of 6 M KOH

9

and 03 M Zn(Ac)2 among these different electrolytes

Fig S11 (a-c) Electrochemical properties of flexible ZnBi2O3 using sodium

polyacrylate (PANa) hydrogel CV curve of at 02 mV sndash1 (a) discharge-charge

profile at 1 A g-1 capacity versus cycle number at 1 A g-1(c) (d) a picture illustration

of two-connected flexible battery devices powering an electrical watch

References

[1] AM Espinosa MT San Joseacute ML Tascoacuten MD Vaacuteszquez P Saacutenchez Batanero Electrochimica Acta 36 (1991) 1561-1571[2] D Wang L Wang G Liang H Li Z Liu Z Tang J Liang C Zhi ACS Nano 13 (2019) 10643-10652[3] M Yan P He Y Chen S Wang Q Wei K Zhao X Xu Q An Y Shuang Y Shao KT Mueller L Mai J Liu J Yang Advanced Materials 30 (2018) 1703725[4] H Wang Y Liang M Gong Y Li W Chang T Mefford J Zhou J Wang T

10

Regier F Wei H Dai Nature Communications 3 (2012) 917[5] Y Zeng Z Lin Y Meng Y Wang M Yu X Lu Y Tong Advanced Materials 28 (2016) 9188-9195[6] R Liu L Ma G Niu X Li E Li Y Bai G Yuan Advanced Functional Materials 27 (2017) 1701635[7] H Xu X Hu H Yang Y Sun C Hu Y Huang Advanced Energy Materials 5 (2015) 1401882[8] W Fang L Fan Y Zhang Q Zhang Y Yin N Zhang K Sun Ceramics International 43 (2017) 8819-8823[9] SX Wang CC Jin WJ Qian Journal of Alloys and Compounds 615 (2014) 12-17[10]AR Mainar E Iruin LC Colmenares A Kvasha I De Meatza M Bengoechea O Leonet I Boyano Z Zhang JA Blazquez Journal of Energy Storage 15 (2018) 304-328[11] A R Mainar O Leonet M Bengoechea I Boyano I De Meatza A Kvasha A Guerfi J Alberto Blaacutezquez International Journal of Energy Research 40 (2016) 1032-1049[12]R Shivkumar G Paruthimal Kalaignan T Vasudevan Journal of Power Sources 55 (1995) 53-62[13]H Li L Ma C Han Z Wang Z Liu Z Tang C Zhi Nano Energy 62 (2019) 550-587[14]W Shang W Yu P Tan B Chen Z Wu H Xu M Ni Journal of Materials Chemistry A 7 (2019) 15564-15574[15]P Gu M Zheng Q Zhao X Xiao H Xue H Pang Journal of Materials Chemistry A 5 (2017) 7651-7666[16]Y Huang Z Li Z Pei Z Liu H Li M Zhu J Fan Q Dai M Zhang L Dai C Zhi Advanced Energy Materials 8 (2018) 1802288[17]L Ma S Chen D Wang Q Yang F Mo G Liang N Li H Zhang JA Zapien C Zhi Advanced Energy Materials 9 (2019) 1803046

11

Fig S7 XRD patterns of the discharge product and the corresponding standard pattern

of Bi

Fig S8 Raman spectra of cathodes collected at different discharge-charge stages the

stages are labeled in Fig 4b

6

Fig S9 Evaluation of stability of Bi2O3 cathode after cycled for different cycles The

first two cycles were performed on Bi2O3 cathodes with a content of 90 wt and 5 wt

for Bi2O3 and carbon black respectively while for longer cycles the content of

Bi2O3 is 80 wt with the carbon black of 10 wt

7

Fig S10 Electrochemical performance of Bi2O3 in mild electrolyte (a b) CV curve

and cycle performance in 3 M Zn(CF3SO3)2 with the inset showing the corresponding

charge-discharge curves at the 10th cycle (c d) CV curve and cycle performance in 2

M ZnSO4 with the inset showing the corresponding charge-discharge curves at the

10th cycle (e f) Cycle performance and the 10th charge-discharge curves in 1M KOH

When 3 M Zn(CF3SO3)2 and 2 M ZnSO4 was used as electrolyte obviously the

overpotential largely increased with the discharge voltage shifted to 017 V (Fig

8

S10a) and 045 V (Fig S10c) respectively In addition two-step reaction appeared

instead of the single transition as certificated by the two pairs of redox peaks in the

CV curves Most importantly limited capacity and poor cycle stability was delivered

in the two mild electrolytes as shown in Fig S10b and d In contrast when 1 M KOH

electrolyte is used the activity was boosted as shown in Fig S10e and f the capacity

was lifted to be over 200 mAh gndash1 and the overpotential decreased largely with the

flat plateau appeared However the cycling performance was poor faded to almost 0

after only 20 cycles which cannot compare with that in 6 M KOH+03 M Zn(Ac)2

Other work already reported that Bi2O3 or Bi are reversible in 1 M KOH and 6 M

KOH with the reaction between Bi2O3 and Bi[8-9] Thus the different electrochemical

behaviors of the batteries with different electrolyte can be ascribed to the Zn anode

The rechargeability of zinc batteries is in relation to the anode issues which are

closely affected by the electrolyte nature[10] Large amounts of research work reveal

that in alkaline electrolyte the reversibility and lifetime rely on the concentration of

KOH[10-13] While the increase of KOH concentration decreases the electrode potential

the conductivity and exchange current associated with reaction kinetics increase

reaching a maximum at about 33 (6 M)[12 14-15] Thatrsquos why the overpotential of Zn-

Bi2O3 in 1M KOH is larger than that in 6 M KOH and the lifetime in 6 M KOH is

higher than that in 1 M KOH However another problem arises as the strong alkaline

electrolytes (6 M KOH) cause a high solubility of zinc an effective method to reduce

the solubility is to use additives including Zn(Ac)2[14 16-17] ZnO[12] and KF[12] etc

Therefore Zn-Bi2O3 delivered the best performance in the electrolyte of 6 M KOH

9

and 03 M Zn(Ac)2 among these different electrolytes

Fig S11 (a-c) Electrochemical properties of flexible ZnBi2O3 using sodium

polyacrylate (PANa) hydrogel CV curve of at 02 mV sndash1 (a) discharge-charge

profile at 1 A g-1 capacity versus cycle number at 1 A g-1(c) (d) a picture illustration

of two-connected flexible battery devices powering an electrical watch

References

[1] AM Espinosa MT San Joseacute ML Tascoacuten MD Vaacuteszquez P Saacutenchez Batanero Electrochimica Acta 36 (1991) 1561-1571[2] D Wang L Wang G Liang H Li Z Liu Z Tang J Liang C Zhi ACS Nano 13 (2019) 10643-10652[3] M Yan P He Y Chen S Wang Q Wei K Zhao X Xu Q An Y Shuang Y Shao KT Mueller L Mai J Liu J Yang Advanced Materials 30 (2018) 1703725[4] H Wang Y Liang M Gong Y Li W Chang T Mefford J Zhou J Wang T

10

Regier F Wei H Dai Nature Communications 3 (2012) 917[5] Y Zeng Z Lin Y Meng Y Wang M Yu X Lu Y Tong Advanced Materials 28 (2016) 9188-9195[6] R Liu L Ma G Niu X Li E Li Y Bai G Yuan Advanced Functional Materials 27 (2017) 1701635[7] H Xu X Hu H Yang Y Sun C Hu Y Huang Advanced Energy Materials 5 (2015) 1401882[8] W Fang L Fan Y Zhang Q Zhang Y Yin N Zhang K Sun Ceramics International 43 (2017) 8819-8823[9] SX Wang CC Jin WJ Qian Journal of Alloys and Compounds 615 (2014) 12-17[10]AR Mainar E Iruin LC Colmenares A Kvasha I De Meatza M Bengoechea O Leonet I Boyano Z Zhang JA Blazquez Journal of Energy Storage 15 (2018) 304-328[11] A R Mainar O Leonet M Bengoechea I Boyano I De Meatza A Kvasha A Guerfi J Alberto Blaacutezquez International Journal of Energy Research 40 (2016) 1032-1049[12]R Shivkumar G Paruthimal Kalaignan T Vasudevan Journal of Power Sources 55 (1995) 53-62[13]H Li L Ma C Han Z Wang Z Liu Z Tang C Zhi Nano Energy 62 (2019) 550-587[14]W Shang W Yu P Tan B Chen Z Wu H Xu M Ni Journal of Materials Chemistry A 7 (2019) 15564-15574[15]P Gu M Zheng Q Zhao X Xiao H Xue H Pang Journal of Materials Chemistry A 5 (2017) 7651-7666[16]Y Huang Z Li Z Pei Z Liu H Li M Zhu J Fan Q Dai M Zhang L Dai C Zhi Advanced Energy Materials 8 (2018) 1802288[17]L Ma S Chen D Wang Q Yang F Mo G Liang N Li H Zhang JA Zapien C Zhi Advanced Energy Materials 9 (2019) 1803046

11

Fig S9 Evaluation of stability of Bi2O3 cathode after cycled for different cycles The

first two cycles were performed on Bi2O3 cathodes with a content of 90 wt and 5 wt

for Bi2O3 and carbon black respectively while for longer cycles the content of

Bi2O3 is 80 wt with the carbon black of 10 wt

7

Fig S10 Electrochemical performance of Bi2O3 in mild electrolyte (a b) CV curve

and cycle performance in 3 M Zn(CF3SO3)2 with the inset showing the corresponding

charge-discharge curves at the 10th cycle (c d) CV curve and cycle performance in 2

M ZnSO4 with the inset showing the corresponding charge-discharge curves at the

10th cycle (e f) Cycle performance and the 10th charge-discharge curves in 1M KOH

When 3 M Zn(CF3SO3)2 and 2 M ZnSO4 was used as electrolyte obviously the

overpotential largely increased with the discharge voltage shifted to 017 V (Fig

8

S10a) and 045 V (Fig S10c) respectively In addition two-step reaction appeared

instead of the single transition as certificated by the two pairs of redox peaks in the

CV curves Most importantly limited capacity and poor cycle stability was delivered

in the two mild electrolytes as shown in Fig S10b and d In contrast when 1 M KOH

electrolyte is used the activity was boosted as shown in Fig S10e and f the capacity

was lifted to be over 200 mAh gndash1 and the overpotential decreased largely with the

flat plateau appeared However the cycling performance was poor faded to almost 0

after only 20 cycles which cannot compare with that in 6 M KOH+03 M Zn(Ac)2

Other work already reported that Bi2O3 or Bi are reversible in 1 M KOH and 6 M

KOH with the reaction between Bi2O3 and Bi[8-9] Thus the different electrochemical

behaviors of the batteries with different electrolyte can be ascribed to the Zn anode

The rechargeability of zinc batteries is in relation to the anode issues which are

closely affected by the electrolyte nature[10] Large amounts of research work reveal

that in alkaline electrolyte the reversibility and lifetime rely on the concentration of

KOH[10-13] While the increase of KOH concentration decreases the electrode potential

the conductivity and exchange current associated with reaction kinetics increase

reaching a maximum at about 33 (6 M)[12 14-15] Thatrsquos why the overpotential of Zn-

Bi2O3 in 1M KOH is larger than that in 6 M KOH and the lifetime in 6 M KOH is

higher than that in 1 M KOH However another problem arises as the strong alkaline

electrolytes (6 M KOH) cause a high solubility of zinc an effective method to reduce

the solubility is to use additives including Zn(Ac)2[14 16-17] ZnO[12] and KF[12] etc

Therefore Zn-Bi2O3 delivered the best performance in the electrolyte of 6 M KOH

9

and 03 M Zn(Ac)2 among these different electrolytes

Fig S11 (a-c) Electrochemical properties of flexible ZnBi2O3 using sodium

polyacrylate (PANa) hydrogel CV curve of at 02 mV sndash1 (a) discharge-charge

profile at 1 A g-1 capacity versus cycle number at 1 A g-1(c) (d) a picture illustration

of two-connected flexible battery devices powering an electrical watch

References

[1] AM Espinosa MT San Joseacute ML Tascoacuten MD Vaacuteszquez P Saacutenchez Batanero Electrochimica Acta 36 (1991) 1561-1571[2] D Wang L Wang G Liang H Li Z Liu Z Tang J Liang C Zhi ACS Nano 13 (2019) 10643-10652[3] M Yan P He Y Chen S Wang Q Wei K Zhao X Xu Q An Y Shuang Y Shao KT Mueller L Mai J Liu J Yang Advanced Materials 30 (2018) 1703725[4] H Wang Y Liang M Gong Y Li W Chang T Mefford J Zhou J Wang T

10

Regier F Wei H Dai Nature Communications 3 (2012) 917[5] Y Zeng Z Lin Y Meng Y Wang M Yu X Lu Y Tong Advanced Materials 28 (2016) 9188-9195[6] R Liu L Ma G Niu X Li E Li Y Bai G Yuan Advanced Functional Materials 27 (2017) 1701635[7] H Xu X Hu H Yang Y Sun C Hu Y Huang Advanced Energy Materials 5 (2015) 1401882[8] W Fang L Fan Y Zhang Q Zhang Y Yin N Zhang K Sun Ceramics International 43 (2017) 8819-8823[9] SX Wang CC Jin WJ Qian Journal of Alloys and Compounds 615 (2014) 12-17[10]AR Mainar E Iruin LC Colmenares A Kvasha I De Meatza M Bengoechea O Leonet I Boyano Z Zhang JA Blazquez Journal of Energy Storage 15 (2018) 304-328[11] A R Mainar O Leonet M Bengoechea I Boyano I De Meatza A Kvasha A Guerfi J Alberto Blaacutezquez International Journal of Energy Research 40 (2016) 1032-1049[12]R Shivkumar G Paruthimal Kalaignan T Vasudevan Journal of Power Sources 55 (1995) 53-62[13]H Li L Ma C Han Z Wang Z Liu Z Tang C Zhi Nano Energy 62 (2019) 550-587[14]W Shang W Yu P Tan B Chen Z Wu H Xu M Ni Journal of Materials Chemistry A 7 (2019) 15564-15574[15]P Gu M Zheng Q Zhao X Xiao H Xue H Pang Journal of Materials Chemistry A 5 (2017) 7651-7666[16]Y Huang Z Li Z Pei Z Liu H Li M Zhu J Fan Q Dai M Zhang L Dai C Zhi Advanced Energy Materials 8 (2018) 1802288[17]L Ma S Chen D Wang Q Yang F Mo G Liang N Li H Zhang JA Zapien C Zhi Advanced Energy Materials 9 (2019) 1803046

11

Fig S10 Electrochemical performance of Bi2O3 in mild electrolyte (a b) CV curve

and cycle performance in 3 M Zn(CF3SO3)2 with the inset showing the corresponding

charge-discharge curves at the 10th cycle (c d) CV curve and cycle performance in 2

M ZnSO4 with the inset showing the corresponding charge-discharge curves at the

10th cycle (e f) Cycle performance and the 10th charge-discharge curves in 1M KOH

When 3 M Zn(CF3SO3)2 and 2 M ZnSO4 was used as electrolyte obviously the

overpotential largely increased with the discharge voltage shifted to 017 V (Fig

8

S10a) and 045 V (Fig S10c) respectively In addition two-step reaction appeared

instead of the single transition as certificated by the two pairs of redox peaks in the

CV curves Most importantly limited capacity and poor cycle stability was delivered

in the two mild electrolytes as shown in Fig S10b and d In contrast when 1 M KOH

electrolyte is used the activity was boosted as shown in Fig S10e and f the capacity

was lifted to be over 200 mAh gndash1 and the overpotential decreased largely with the

flat plateau appeared However the cycling performance was poor faded to almost 0

after only 20 cycles which cannot compare with that in 6 M KOH+03 M Zn(Ac)2

Other work already reported that Bi2O3 or Bi are reversible in 1 M KOH and 6 M

KOH with the reaction between Bi2O3 and Bi[8-9] Thus the different electrochemical

behaviors of the batteries with different electrolyte can be ascribed to the Zn anode

The rechargeability of zinc batteries is in relation to the anode issues which are

closely affected by the electrolyte nature[10] Large amounts of research work reveal

that in alkaline electrolyte the reversibility and lifetime rely on the concentration of

KOH[10-13] While the increase of KOH concentration decreases the electrode potential

the conductivity and exchange current associated with reaction kinetics increase

reaching a maximum at about 33 (6 M)[12 14-15] Thatrsquos why the overpotential of Zn-

Bi2O3 in 1M KOH is larger than that in 6 M KOH and the lifetime in 6 M KOH is

higher than that in 1 M KOH However another problem arises as the strong alkaline

electrolytes (6 M KOH) cause a high solubility of zinc an effective method to reduce

the solubility is to use additives including Zn(Ac)2[14 16-17] ZnO[12] and KF[12] etc

Therefore Zn-Bi2O3 delivered the best performance in the electrolyte of 6 M KOH

9

and 03 M Zn(Ac)2 among these different electrolytes

Fig S11 (a-c) Electrochemical properties of flexible ZnBi2O3 using sodium

polyacrylate (PANa) hydrogel CV curve of at 02 mV sndash1 (a) discharge-charge

profile at 1 A g-1 capacity versus cycle number at 1 A g-1(c) (d) a picture illustration

of two-connected flexible battery devices powering an electrical watch

References

[1] AM Espinosa MT San Joseacute ML Tascoacuten MD Vaacuteszquez P Saacutenchez Batanero Electrochimica Acta 36 (1991) 1561-1571[2] D Wang L Wang G Liang H Li Z Liu Z Tang J Liang C Zhi ACS Nano 13 (2019) 10643-10652[3] M Yan P He Y Chen S Wang Q Wei K Zhao X Xu Q An Y Shuang Y Shao KT Mueller L Mai J Liu J Yang Advanced Materials 30 (2018) 1703725[4] H Wang Y Liang M Gong Y Li W Chang T Mefford J Zhou J Wang T

10

Regier F Wei H Dai Nature Communications 3 (2012) 917[5] Y Zeng Z Lin Y Meng Y Wang M Yu X Lu Y Tong Advanced Materials 28 (2016) 9188-9195[6] R Liu L Ma G Niu X Li E Li Y Bai G Yuan Advanced Functional Materials 27 (2017) 1701635[7] H Xu X Hu H Yang Y Sun C Hu Y Huang Advanced Energy Materials 5 (2015) 1401882[8] W Fang L Fan Y Zhang Q Zhang Y Yin N Zhang K Sun Ceramics International 43 (2017) 8819-8823[9] SX Wang CC Jin WJ Qian Journal of Alloys and Compounds 615 (2014) 12-17[10]AR Mainar E Iruin LC Colmenares A Kvasha I De Meatza M Bengoechea O Leonet I Boyano Z Zhang JA Blazquez Journal of Energy Storage 15 (2018) 304-328[11] A R Mainar O Leonet M Bengoechea I Boyano I De Meatza A Kvasha A Guerfi J Alberto Blaacutezquez International Journal of Energy Research 40 (2016) 1032-1049[12]R Shivkumar G Paruthimal Kalaignan T Vasudevan Journal of Power Sources 55 (1995) 53-62[13]H Li L Ma C Han Z Wang Z Liu Z Tang C Zhi Nano Energy 62 (2019) 550-587[14]W Shang W Yu P Tan B Chen Z Wu H Xu M Ni Journal of Materials Chemistry A 7 (2019) 15564-15574[15]P Gu M Zheng Q Zhao X Xiao H Xue H Pang Journal of Materials Chemistry A 5 (2017) 7651-7666[16]Y Huang Z Li Z Pei Z Liu H Li M Zhu J Fan Q Dai M Zhang L Dai C Zhi Advanced Energy Materials 8 (2018) 1802288[17]L Ma S Chen D Wang Q Yang F Mo G Liang N Li H Zhang JA Zapien C Zhi Advanced Energy Materials 9 (2019) 1803046

11

S10a) and 045 V (Fig S10c) respectively In addition two-step reaction appeared

instead of the single transition as certificated by the two pairs of redox peaks in the

CV curves Most importantly limited capacity and poor cycle stability was delivered

in the two mild electrolytes as shown in Fig S10b and d In contrast when 1 M KOH

electrolyte is used the activity was boosted as shown in Fig S10e and f the capacity

was lifted to be over 200 mAh gndash1 and the overpotential decreased largely with the

flat plateau appeared However the cycling performance was poor faded to almost 0

after only 20 cycles which cannot compare with that in 6 M KOH+03 M Zn(Ac)2

Other work already reported that Bi2O3 or Bi are reversible in 1 M KOH and 6 M

KOH with the reaction between Bi2O3 and Bi[8-9] Thus the different electrochemical

behaviors of the batteries with different electrolyte can be ascribed to the Zn anode

The rechargeability of zinc batteries is in relation to the anode issues which are

closely affected by the electrolyte nature[10] Large amounts of research work reveal

that in alkaline electrolyte the reversibility and lifetime rely on the concentration of

KOH[10-13] While the increase of KOH concentration decreases the electrode potential

the conductivity and exchange current associated with reaction kinetics increase

reaching a maximum at about 33 (6 M)[12 14-15] Thatrsquos why the overpotential of Zn-

Bi2O3 in 1M KOH is larger than that in 6 M KOH and the lifetime in 6 M KOH is

higher than that in 1 M KOH However another problem arises as the strong alkaline

electrolytes (6 M KOH) cause a high solubility of zinc an effective method to reduce

the solubility is to use additives including Zn(Ac)2[14 16-17] ZnO[12] and KF[12] etc

Therefore Zn-Bi2O3 delivered the best performance in the electrolyte of 6 M KOH

9

and 03 M Zn(Ac)2 among these different electrolytes

Fig S11 (a-c) Electrochemical properties of flexible ZnBi2O3 using sodium

polyacrylate (PANa) hydrogel CV curve of at 02 mV sndash1 (a) discharge-charge

profile at 1 A g-1 capacity versus cycle number at 1 A g-1(c) (d) a picture illustration

of two-connected flexible battery devices powering an electrical watch

References

[1] AM Espinosa MT San Joseacute ML Tascoacuten MD Vaacuteszquez P Saacutenchez Batanero Electrochimica Acta 36 (1991) 1561-1571[2] D Wang L Wang G Liang H Li Z Liu Z Tang J Liang C Zhi ACS Nano 13 (2019) 10643-10652[3] M Yan P He Y Chen S Wang Q Wei K Zhao X Xu Q An Y Shuang Y Shao KT Mueller L Mai J Liu J Yang Advanced Materials 30 (2018) 1703725[4] H Wang Y Liang M Gong Y Li W Chang T Mefford J Zhou J Wang T

10

Regier F Wei H Dai Nature Communications 3 (2012) 917[5] Y Zeng Z Lin Y Meng Y Wang M Yu X Lu Y Tong Advanced Materials 28 (2016) 9188-9195[6] R Liu L Ma G Niu X Li E Li Y Bai G Yuan Advanced Functional Materials 27 (2017) 1701635[7] H Xu X Hu H Yang Y Sun C Hu Y Huang Advanced Energy Materials 5 (2015) 1401882[8] W Fang L Fan Y Zhang Q Zhang Y Yin N Zhang K Sun Ceramics International 43 (2017) 8819-8823[9] SX Wang CC Jin WJ Qian Journal of Alloys and Compounds 615 (2014) 12-17[10]AR Mainar E Iruin LC Colmenares A Kvasha I De Meatza M Bengoechea O Leonet I Boyano Z Zhang JA Blazquez Journal of Energy Storage 15 (2018) 304-328[11] A R Mainar O Leonet M Bengoechea I Boyano I De Meatza A Kvasha A Guerfi J Alberto Blaacutezquez International Journal of Energy Research 40 (2016) 1032-1049[12]R Shivkumar G Paruthimal Kalaignan T Vasudevan Journal of Power Sources 55 (1995) 53-62[13]H Li L Ma C Han Z Wang Z Liu Z Tang C Zhi Nano Energy 62 (2019) 550-587[14]W Shang W Yu P Tan B Chen Z Wu H Xu M Ni Journal of Materials Chemistry A 7 (2019) 15564-15574[15]P Gu M Zheng Q Zhao X Xiao H Xue H Pang Journal of Materials Chemistry A 5 (2017) 7651-7666[16]Y Huang Z Li Z Pei Z Liu H Li M Zhu J Fan Q Dai M Zhang L Dai C Zhi Advanced Energy Materials 8 (2018) 1802288[17]L Ma S Chen D Wang Q Yang F Mo G Liang N Li H Zhang JA Zapien C Zhi Advanced Energy Materials 9 (2019) 1803046

11

and 03 M Zn(Ac)2 among these different electrolytes

Fig S11 (a-c) Electrochemical properties of flexible ZnBi2O3 using sodium

polyacrylate (PANa) hydrogel CV curve of at 02 mV sndash1 (a) discharge-charge

profile at 1 A g-1 capacity versus cycle number at 1 A g-1(c) (d) a picture illustration

of two-connected flexible battery devices powering an electrical watch

References

[1] AM Espinosa MT San Joseacute ML Tascoacuten MD Vaacuteszquez P Saacutenchez Batanero Electrochimica Acta 36 (1991) 1561-1571[2] D Wang L Wang G Liang H Li Z Liu Z Tang J Liang C Zhi ACS Nano 13 (2019) 10643-10652[3] M Yan P He Y Chen S Wang Q Wei K Zhao X Xu Q An Y Shuang Y Shao KT Mueller L Mai J Liu J Yang Advanced Materials 30 (2018) 1703725[4] H Wang Y Liang M Gong Y Li W Chang T Mefford J Zhou J Wang T

10

Regier F Wei H Dai Nature Communications 3 (2012) 917[5] Y Zeng Z Lin Y Meng Y Wang M Yu X Lu Y Tong Advanced Materials 28 (2016) 9188-9195[6] R Liu L Ma G Niu X Li E Li Y Bai G Yuan Advanced Functional Materials 27 (2017) 1701635[7] H Xu X Hu H Yang Y Sun C Hu Y Huang Advanced Energy Materials 5 (2015) 1401882[8] W Fang L Fan Y Zhang Q Zhang Y Yin N Zhang K Sun Ceramics International 43 (2017) 8819-8823[9] SX Wang CC Jin WJ Qian Journal of Alloys and Compounds 615 (2014) 12-17[10]AR Mainar E Iruin LC Colmenares A Kvasha I De Meatza M Bengoechea O Leonet I Boyano Z Zhang JA Blazquez Journal of Energy Storage 15 (2018) 304-328[11] A R Mainar O Leonet M Bengoechea I Boyano I De Meatza A Kvasha A Guerfi J Alberto Blaacutezquez International Journal of Energy Research 40 (2016) 1032-1049[12]R Shivkumar G Paruthimal Kalaignan T Vasudevan Journal of Power Sources 55 (1995) 53-62[13]H Li L Ma C Han Z Wang Z Liu Z Tang C Zhi Nano Energy 62 (2019) 550-587[14]W Shang W Yu P Tan B Chen Z Wu H Xu M Ni Journal of Materials Chemistry A 7 (2019) 15564-15574[15]P Gu M Zheng Q Zhao X Xiao H Xue H Pang Journal of Materials Chemistry A 5 (2017) 7651-7666[16]Y Huang Z Li Z Pei Z Liu H Li M Zhu J Fan Q Dai M Zhang L Dai C Zhi Advanced Energy Materials 8 (2018) 1802288[17]L Ma S Chen D Wang Q Yang F Mo G Liang N Li H Zhang JA Zapien C Zhi Advanced Energy Materials 9 (2019) 1803046

11

Regier F Wei H Dai Nature Communications 3 (2012) 917[5] Y Zeng Z Lin Y Meng Y Wang M Yu X Lu Y Tong Advanced Materials 28 (2016) 9188-9195[6] R Liu L Ma G Niu X Li E Li Y Bai G Yuan Advanced Functional Materials 27 (2017) 1701635[7] H Xu X Hu H Yang Y Sun C Hu Y Huang Advanced Energy Materials 5 (2015) 1401882[8] W Fang L Fan Y Zhang Q Zhang Y Yin N Zhang K Sun Ceramics International 43 (2017) 8819-8823[9] SX Wang CC Jin WJ Qian Journal of Alloys and Compounds 615 (2014) 12-17[10]AR Mainar E Iruin LC Colmenares A Kvasha I De Meatza M Bengoechea O Leonet I Boyano Z Zhang JA Blazquez Journal of Energy Storage 15 (2018) 304-328[11] A R Mainar O Leonet M Bengoechea I Boyano I De Meatza A Kvasha A Guerfi J Alberto Blaacutezquez International Journal of Energy Research 40 (2016) 1032-1049[12]R Shivkumar G Paruthimal Kalaignan T Vasudevan Journal of Power Sources 55 (1995) 53-62[13]H Li L Ma C Han Z Wang Z Liu Z Tang C Zhi Nano Energy 62 (2019) 550-587[14]W Shang W Yu P Tan B Chen Z Wu H Xu M Ni Journal of Materials Chemistry A 7 (2019) 15564-15574[15]P Gu M Zheng Q Zhao X Xiao H Xue H Pang Journal of Materials Chemistry A 5 (2017) 7651-7666[16]Y Huang Z Li Z Pei Z Liu H Li M Zhu J Fan Q Dai M Zhang L Dai C Zhi Advanced Energy Materials 8 (2018) 1802288[17]L Ma S Chen D Wang Q Yang F Mo G Liang N Li H Zhang JA Zapien C Zhi Advanced Energy Materials 9 (2019) 1803046

11