Advanced LithiumAdvanced Lithium--Ion Battery technologies for plugIon Battery technologies for plug--in in hybrid electric vehicles hybrid electric vehicles

Yaser Abu-Lebdeh and Isobel Davidson

National Research Council of Canada, Ottawa, CANADANational Research Council of Canada, Ottawa, CANADA

Outline

I- Introduction

II- Results• Electrochemical and thermal properties of the new p p f

electrolytes.• Battery testing using the new electrolytes.• Preparation and battery testing of nanoparticles of the high

voltage LiNi0.5Mn1.5O4 cathode material

III- Conclusions

Introduction: Requirements for a battery in HEV/PHEV.

• High power density and energy density.

• An operating temperature range from 30 °C to• An operating temperature range from -30 °C to +50 °C.

L l d lif i il h f h hi l• Long calendar life similar to that of the vehicle.

• Safe: Abuse tolerant especially on Nail and Crush tests when battery components are exposed to air (less reactive anode).

• Cheap.

• Environmentally friendly.y f y

Introduction: Advantages/Disadvantages of Li-ion batteries.

Advantages :

• High operating voltage ~3.7 V. ( three times more than NiMH 1 3 V)~1.3 V).

• High specific and volumetric energy “120-160 Wh/Kg’’. ( two times more than NiMH “60-75 Wh/Kg”).times more than NiMH 60 75 Wh/Kg ).

• Low self discharge (5% per month, over 30% per month NiMH)

• Good cycle life (still to be increased for PHEV applications)• Good cycle life (still to be increased for PHEV applications)

• No memory effect.

Di d tDisadvantages:

• They utilize flammable, volatile, corrosive electrolytes.

• They are more expensive than other battery technologies.

Motivation

I- To replace conventional electrolytes ( e.g. LiPF6 in EC/DMC) by electrolytes that are:

• Safer ( use of “Adiponitrile’’ a solvent with higher boiling point; higher flash point and higher autoignition temperature).

l h ll bl h h l• Electrochemically more stable at high voltages.

II- To produce nano high voltage cathode materials:• This would increase the energy/power density and rate

bili f h b d ibl i f b d icapability of the battery and possibly its safety by rendering the use of Li4Ti5O12 (safe anode ) and retaining the high operating voltage of the batteriesoperating voltage of the batteries

I Adiponitrile, ADN, a thermally and electrochemically stable solventy

• Has low volatility (B.p. ~ 300 °C)

H l fl b l (F 160• Has low flammability (F.p. >160 °C)

• Good solvating properties• Good solvating properties.

• Commercially available and relatively cheap

1,4-Dicyanobutane

relatively cheap.

Mp Bp Fp Tig

DMC 2-4 °C 90 °C 18 °CDEC -43°C 126°C 25°C 445°CEC 34 37 °C 246 7 °C 160 °C 450°CEC 34-37 °C 246.7 °C 160 °C 450°C

ADN 1 °C 295°C 160°C 550°C

ADN electrolyte: cyclic voltammetry

Cyclic voltammetryof anewelectrolyte (sol 2) at 20• The ADN electrolyte made by mixing with the non-corrosive LiTFSI salt (1M) shows a wide

Cyclic voltammetry of a new electrolyte (sol-2) at 20 mV/s and ambient tenperature

2.E-07

3.E-07

LiTFSI salt (1M) shows a wide electrochemical window extending over 6.5 V. -1.E-07

0.E+00

1.E-07

I/ A.

cm2

• This is 1.5 volt higher than the commercial electrolyte

-3.E-07

-2.E-07

-1 0 1 2 3 4 5 6 7E/ V vs Li

ADN electrolyte: Aluminum corrosion

• Aluminum is the preferred current collector in Li-ion batteries 1.E-06collector in Li ion batteries because of its low cost and light weight . 8.E-07

1.E 06

m2

• The ADN electrolyte shows a greater stability against aluminum

i h i i i l

4.E-07

I/ A

/cm

with a re-passivation potential (ER) value of 4.8 V.

• This is 1 volt higher than the

0.E+00

3 4 5 6E/ V Vs Li

ER

• This is 1 volt higher than the commercial electrolyte

E/ V Vs Li

ADN electrolyte: DSC

• The ADN electrolyte is moreADN-1M LiTFSI

45The ADN electrolyte is more thermally stable than the commercially available 25

45

W)

1 M LiPF6 EC:DMC (45 °C). do -15

5

t Flo

w (m

W• The electrolyte has a high

melting point (5 °C).

En

-35Hea

t

-55-100 -50 0 50 100 150

T / ºC

ADN electrolyte: preliminary battery testing

• Initial battery testing showed that the ADN electrolyte does not work in a batteryelectrolyte does not work in a battery

• E l ti ADN i t bl t f t• Explanation: ADN is not able to form a compact, conducting solid electrolyte interface, SEI.

• Solution: we need to add EC (ethylene carbonate, a good SEI former) as a co solvent (1:1 v/v) orgood SEI former) as a co-solvent (1:1 v/v) or additive (1:19 v/v or 5 w.t.%)

EC:ADN electrolytes: DSC

• The 1:1 electrolyte is a miscible solution with a 45 ADN-1M LiTFSImiscible solution with a low melting point.

• The 1:19 still shows the25

45

W)

1:1 EC:ADN(1MLiTFSI)1:19 EC:ADN(1MLiTFSI)

The 1:19 still shows the 5 °C melting peak.

• The 1:1 and 1:19 End

o-15

5

at F

low

(mW

electrolytes are more thermally stable than the

i ll il bl 1

-35

Hea

commercially available 1 M LiPF6 EC:DMC (45 °C).

-55-100 -50 0 50 100 150

T / ºC(45 C).

EC:ADN electrolytes: Conductivity

• All the electrolytes showed• All the electrolytes showed good conductivities exceeding 1 mS/cm at ADN 1:1 EC:ADN 1:!9 EC:ADN

20 °C.

• The 1:1 And the 1:19

1.E-01

m)

ADN 1:1 EC:ADN 1:!9 EC:ADN

increased the conductivity of ADN reaching in the case of 1:1 to 3 4 mS/cm at 1 E-03

1.E-02

uctiv

ity (S

/ccase of 1:1 to 3.4 mS/cm at 20 °C.

• LiBoB salt, a good SEI 1.E-04

1.E 03C

ondu

LiBoB salt, a good SEI former, was found to have limited solubility in ADN

-40 -20 0 20 40 60 80 100

T / ºC

( 0.17 M) was added to the electrolyte (0.1 M).

Battery performance: Electrolyte: EC:ADN (1:1)1M LiTFSI + 0.1 M LiBoB; Electrodes: Graphite/LiCoO2

Cell 22 -V oltage P rofile4 5

• Batteries using ADN with no EC or LiBoB do not

LiCoO 2/1:1 E C:A DN, 0.1M LiB OB , 1M LiTFS I/Gr

2.5

3

3.5

4

4.5

tial (

V)

work.

• When EC is used along i h LiB B h b

0.5

1

1.5

2

Pote

nt

with LiBoB the battery gives good capacity.

• The 1:1 EC:ADN gives

00 20000 40000 60000 80000 100000 120000 140000

T est T ime (S)

Effect of EC and LiBoB on Specific Capacity and Cyclability for Gr/LiCoO2 Battery

120

• The 1:1 EC:ADN gives initial discharge capacity of 115 mAh/g with good

y

60

80

100ci

ty (m

Ah/g

)

1:1 ADN:EC 1M LiTFSI, 0.1M LiBoB

No LiBoB & No EC

retention up to the 50th

cycle.20

40

60

Spec

ific

Cap

ac No LiBoB & No EC

No EC

00 10 20 30 40 50Cycle #

Battery performance: Electrolyte: EC:ADN (1:19)1M LiTFSI + 0.1 M LiBoB; Electrodes: Graphite/LiCoO2

FiRE15 -Voltage Profile LiCoO2/1:19 EC:ADN (1M LiTFSI, 0.1M LiBOB)/ MC-MB

3.54

4.5

22.5

3

oten

tial (

V)

• Initial discharge capacity 0

0.51

1.5Po

g p yof 110 mAh/g with little loss up to 50 cycles.

00 20000 40000 60000 80000 100000 120000

Time (S)

F iR E 1 5 - D is c ha rge C a pa c ity v s C y c le # :120

• Excellent coulombic efficiency.

F iR E 1 5 D is c ha rge C a pa c ity v s C y c le # :L iC o O 2/1 :1 9 E C :AD N (1 M L iTF S I, 0 .1 M L iB O B )/G r

80

100

120

y (m

Ah/

g)

2 0

40

60

Spe

cific

Cap

acity

0

20

0 10 20 30 40 50C yc le #

S

Battery performance: Effect of Diphenyl, DP, 2 w.t.% electrolyte additive : EC:ADN

• DP shows no effect FiRE33 - Voltage Profile4 5FiRE33 -Discharge Capacity vs Cycle #:120• DP shows no effect

on the capacity of

1:19.

LiCoO2/1:19 EC:ADN(by wt) +DP (1M LiTFSI, 0.1M LiBOB)/Gr

2 5

3.0

3.5

4.0

4.5

al (V

)

F iRE33 Discharge Capacity vs Cycle #:LiCoO 2/1:19 (w t) EC:ADN +DP (1M L iTFS I, 0 .1M L iB OB)/G r

80

100

120

city

(mAh

/g)

• DP improves the

capacity and 0.5

1.0

1.5

2.0

2.5

Pote

ntia

20

40

60S

peci

fic C

apac

cyclability of the 1:1

electrolyte.

Di h i

0.00 50000 100000 150000

Test Time (S)

00 10 20 30 40 50

C yc le #

FiRE29 Discharge Capacity vs Cycle #:120 FiRE29-VoltageProfile:• Discharge capacity

of 80 mAh/g for the

1:19 after the 50th

FiRE29 - Discharge Capacity vs Cycle #:LiCoO2/1:1 EC:ADN(by wt) +DP (1M LiTFSI, 0.1M LiBOB)/Gr

80

100

120

y (m

Ah/g

)

FiRE29 Voltage Profile:LiCoO2/1:1 EC:ADN(by wt) +DP (1M LiTFSI, 0.1M LiBOB)/Gr

3.03.54.04.5

(V)

f

cyclcle and 95

mAh/g for the 1:1 20

40

60

Spec

ific

Cap

acity

051.01.52.02.5

Pote

ntia

lafter the 30th

0

20

0 5 10 15 20 25 30Cycle #

S

0.00.5

0 40000 80000 120000Test Time(S)

Battery performance: Effect of Vinylidene carbonate (VC) , 2 w.t.% electrolyte additive : EC:ADN

FiRE32 - Discharge Capacity vs Cycle #120 FiRE32-VoltageProfile

• VC decreased the discharge

g p y yLiCoO2/1:19 EC:ADN(by wt) +VC (1M LiTFSI, 0.1M LiBOB)/Gr

80

100

120

city

(mA

h/g)

FiRE32 Voltage ProfileLiCoO2/1:19 EC:ADN(by wt) +VC (1M LiTFSI, 0.1M LiBOB)/Gr

3.03.5

4.04.5

(V)

capacity of the two electrolytes.

Th d20

40

60S

peci

fic C

apac

05

1.01.5

2.02.5

Pote

ntia

l

• The decrease was more detrimental in

00 10 20 30 40 50

Cycle #

FiRE39 - Discharge Capacity vs Cycle #: FiRE39 Voltage Profile

0.00.5

0 20000 40000 60000 80000 100000 120000Test Time (S)

detrimental in the case of the 1:1 as the

FiRE39 Discharge Capacity vs Cycle #:LiCoO2/1:1 EC:ADN(by wt) +VC (1M LiTFSI, 0.1M LiBOB)/Gr

50

60

70

80

(mA

h/g)

FiRE39 - Voltage Profile LiCoO2/1:1 EC:ADN(by wt) +VC (1M LiTFSI, 0.1M LiBOB)/Gr

3.0

3.5

4.0

4.5

V)

capacity reached 60 mAh/g by the 20

30

40

50

peci

fic C

apac

ity

1.0

1.5

2.0

2.5

Pot

entia

l (V

mAh/g by the 50th cycle. 0

10

0 10 20 30 40 50Cycle #

S

0.0

0.5

0 20000 40000 60000 80000Test Time (S)

Battery performance: Electrolyte: EC:ADN 1M LiTFSI Electrodes: Graphite/Li Metal

• Batteries using ADN with noBatteries using ADN with no LiBoB or EC do not work.

• Batteries using ADN with EC only showed very low capacity

Effect of EC and LiBoB on Capacity and Cyclability for Li Metal/LiCoO2 Battery

160only showed very low capacity.• Batteries using ADN with LiBoB

show good capacity of 100-120 Ah/ b t th di b th 30th

120

140

160

ty (m

Ah/

g

mAh/g but they die by the 30th

cycle.• Batteries using ADN with EC

l i h LiB B d60

80

100

fic C

apac

it1:1 ADN:EC (1M LiTFSI, 0.1 M LiBoB)

No LiBOB

along with LiBoB gave good capacity.

• The 1:1 EC:ADN electrolyte 0

20

40S

peci

fNo EC

No EC & No LiBoB

gave initial discharge capacities of 150 mAh/g with gradual loss reaching 105 mAh/g by the 40th

l

0 10 20 30 40

Cycle #

cycle.

II High voltage nano-cathode material

LiNi M O h• LiNi0.5Mn1.5O4 shows good cycling and high capacity at a high voltagecapacity at a high voltage of ~ 4.7 V.

• A new method based on the combination of sol-gel and microwave assisted

h i d l dsynthesis was developed.

• TEM showed that thematerial has nanoparticlesmaterial has nanoparticleswith an average of 40 nmin diameter.

• XRD showed a pure phase

Battery testing of the new nano-cathode

B i b d h 5• Batteries based on the new nano-cathode and Li metal as ananode in a conventional 4

4.5

5

ge (V

)

anode in a conventionalelectrolyte showed a firstdischarge capacity of 118 mAh/g.

3.5

4

Vol

tag

chargedischarge

• The batteries showed moderate

30 50 100 150 200

Capacity (mA/g)

180capacity retention upon cycling.

• Coulombic efficiency improvedli

100120140160180

(mAh

/g

ChargeDischarge

upon cycling.

20406080

Capa

city

00 10 20 30 40 50

Cycle number

Conclusions

W h id ifi d f il f f d l h i ll• We have identified a new family of safer and more electrochemically stable electrolytes that work well in Li-ion batteries.

• The electrolyte is based on adiponitrile a dinitrile solvent which we• The electrolyte is based on adiponitrile, a dinitrile solvent which we found that it needs to be coupled with EC as a co-solvent or an additive in order to function in a Li metal or Li-ion battery.

• Li-ion batteries using Graphite/LiCoO2 electrodes and the new electrolytes showed capacities reaching 120 mAh/g in the case of 1:1 by volume EC:ADN.

• Organic additives were added to the electrolytes and one DP showed i d i d li hil h h VC d d himproved capacity and cycling while the other VC decreased the capacity.

• A 4 7 V LiNi Mn O nano cathode material (40 nm) was prepared• A 4.7 V LiNi0.5Mn1.5O4 nano-cathode material (40 nm) was prepared and showed improved capacity and cycling.

Acknowledgements

• Svetlana Niketic• Sapphire Vanderlippp p• Vivian Ng• Ali AbouimraneAli Abouimrane