Room Temperature Na-ion Battery Development

Xiaolin Li, Jun Liu, Yuyan Shao, Huilin Pan, Pengfei Yan,

Chongmin Wang, Wei Wang, Vincent L. Sprenkle

Pacific Northwest National Laboratory

Electrochemical Materials and Systems

DOE Office of Electricity Energy Storage Program – Imre Gyuk

Program Manager.

OE Energy Storage Systems Program Review

September 16-19th, 2014

Outline

1. Introduction

Advantages and challenges of Na-ion batteries

Current status and perspective

2. Overview of our previous work

3. Progress of FY14

i) Optimization of Na0.44MnO2 (C)-hard carbon (A) chemistry

ii) Development of phosphate (Na3V2(PO4)3) cathode

iii) Exploration of Prussian blue cathode materials

4. Summary and Future work

1

2

Advantages:

Na-ion batteries are very similar to Li-ion

batteries in many ways

Potentially can have a high energy density

e.g. >300 Wh/kg (material level estimation),

~150 Wh/kg (cell level estimation)

Operate at room temperature

Na sources are more abundant than Li and

geographically uniformly distributed

Li2CO3 (~$5000/ton)

http://www.lithiumsite.com/market.html

Na2CO3 (~$150/ton)

Sodium-ion batteries are a type of reusable battery that uses sodium-ions as

its charge carriers. (http://en.wikipedia.org/wiki/Sodium-ion_battery)

Why Na-ion Batteries

1. M. d. Slater, et al. Adv. Funct. Mater. 2013, 23, 947.

2. S. P. Ong, et al. Energy Environ. Sci.. 2011, 4, 3680.

Energy densities for various Na-ion systems

*calculated using the BatPaC model software package. **average discharge voltage =3.3V, power/energy ratio =2. ***Standard Li-ion cell energy density calculated with the

same technique range from 160 to 210 Wh/kg.

3

Na-ion is ~30% larger than Li-ion in diameter and ~2 times heavier.

~ lower gravimetric capacity than Li-ion batteries.

Na metal standard electrode potential is ~0.3V higher than Li.

Low cathode voltage and high anode voltage; low cell voltage

Na metal is more active than Li

Cathode,

Anode,

Electrolyte

Challenges

4

Current Status

H.L. Pan, et al. Energy Environ. Sci. 2013, 6, 2338

Chart of cathode and anode materials for Na-ion batteries

5

Current Status

Na3V2(PO4)3

1. C.B.. Zhu, et al. Nano Lett. 2014, 14, 2175.

2. L. Wang, et al. Angew. Chem. Int. Ed. 2013, 52, 1964.

Na3V2(PO4)3 and Prussian blue materials are promising cathodes with high

capacites (~120 mAh/g), good cycling stability, and rate performance.

Na1.72MnFe(CN)6 and Na1.40MnFe(CN)6

6

Our Perspective

PNNL will demonstrate potentially low cost full cell Na-ion batteries

with high capacity and long cycling stability for grid scale applications

7

Overview of Our Previous Work

0 500 1000 15000

50

100

150

Discharge capacity

Sp

ecif

ic c

ap

acit

y (

mA

h/g

)

Cycle number

Y. L. Cao, et al. Adv. Mater., 2011, 23, 3155

Na0.44MnO2 nanowires synthesized using a polymer-pyrolysis method showed excellent

cycling stability in half-cell design with ~79% capacity retention over 1500 cycles at 0.5C rate.

The Na0.44MnO2 obtained by ball milling method has good cycling stability with ~95% capacity

retention over 300 cycles at 1c rate (1C = 120 mA/g).

Na0.44MnO2 half cell

0 100 200 3000

20

40

60

80

100

120

140

Discharge capacityS

pecif

ic c

ap

acit

y (

mA

h/g

)

Cycle number

0

25

50

75

100

Coulombic efficiency

Co

ulo

mb

ic E

ffic

ien

cy (

%)

1C rate

Na0.44MnO2 nanowires by pyrolysis

0.5C

rate

Na0.44MnO2 by ball milling

8

0 100 200 300 400 500 600 700 800 900 10000

20

40

60

80

100

120

140

Discharge capacity

Sp

ecif

ic c

ap

acit

y (

mA

h/g

)

Cycle number

0

25

50

75

100

Coulombic efficiency

Co

ulo

mb

ic E

ffic

ien

cy (

%)

2C rate

~83% retention over 1000 cycles

0 20 40 60 80 100 120 1401.5

2.0

2.5

3.0

3.5

4.0

Vo

ltag

e (

V)

Specific capacity (mAh/g)

1st cycle

500th

cycle

1000th

cycle

The full cell of Na0.44MnO2 cathode and hard carbon anode can have excellent

cycling stability and rate performance.

It can have an initial capacity of ~108 mAh/g (corresponding energy density is ~280

Wh/kg) and ~83% capacity retention over 1000 cycles at 2C rate (1C = 120 mA/g).

Overview of Our Previous Work

Na0.44MnO2 – hard carbon full cell

9

0 100 200 300 400 500 600 700 8000

20

40

60

80

100

120

140

Discharge capacity

Sp

ecif

ic c

ap

acit

y (

mA

h/g

)

Cycle number

0

25

50

75

100

Coulombic efficiency

Co

ulo

mb

ic E

ffic

ien

cy (

%)

0.5C rate

~88% retention

over 800 cycles

0 20 40 60 80 1002.5

3.0

3.5

4.0

Vo

ltag

e (

V)

Specific capacity (mAh/g)

100th

cycle

500th

cycle

Na3V2(PO4)3 has a high discharge voltage at ~3.2 V versus Na metal

It has a capacity of ~92 mAh/g at 0. 5C rate and good cycling stability with

~88% capacity retention over 800 cycles (1C = 120 mA/g).

Overview of Our Previous Work

Na3V2(PO4)3–carbon cathode

10

0 500 1000 1500 20000

20

40

60

80

100

120

140

Na0.44

MnO2

Discharge capacity

Sp

ec

ific

ca

pa

cit

y (

mA

h•g

-1)

Cycle number

0.1C

0

20

40

60

80

100

Coulombic efficiency

2.0 to 3.7 V

Co

ulo

mb

ic E

ffic

ien

cy

(%

)1C

0 500 1000 1500 20000

20

40

60

80

100

120

140

Na0.44

MnO2

Discharge capacity

Sp

ecif

ic c

ap

acit

y (

mA

h•g

-1)

Cycle number

0

20

40

60

80

100

Coulombic efficiency

2.0 to 4.0 V

Co

ulo

mb

ic E

ffic

ien

cy (

%)

1C0.1C

i) Optimization of Na0.44MnO2-Hard Carbon Chemistry Optimize the voltage window to improve first cycle Coulombic efficiency

Na0.44MnO2 half cell

The first cycle Coulombic efficiency is improved to >80% when cycling between 2 to 3.7V.

The capacity and cycling stability are almost similar (1C = 120 mA/g).

80% retention

over 2000 cycles

80% retention

over 2000 cycles

0 2 4 6 8 10 12 14 16 18 2060

65

70

75

80

85

90

95

100

105

Na0.44

MnO2

2.0 to 4.0 V

Co

ulo

mb

ic e

ffic

ien

cy

(%

)

Cycle number

0.1C

2.0 to 3.7 V

1C

Enlarged figure to show the Coulombic

efficiency in the first 20 cycles.

11

pristine After 1000 cycles

The structure of Na0.44MnO2 is very stable upon cycling. Its structure doesn’t change

much even after 1000 cycles. It remains to be single crystal.

TEM characterization of the Na0.44MnO2 cathode before and after cycling

Structure Characterization of Na0.44MnO2

12

The specific capacity and energy density are slightly lower when the full cell cycles

between 1.5 to 3.8V.

The cycling stability are almost similar (1C = 120 mA/g).

0 500 1000 1500 20000

20

40

60

80

100

120

140

Na0.44

MnO2-Hard carbon

Discharge capacity

Sp

ecif

ic c

ap

acit

y (

mA

h•g

-1)

Cycle number

0

25

50

75

100

Coulombic efficiency

1.5 to 4.1V

Co

ulo

mb

ic E

ffic

ien

cy (

%)

2C

0 500 1000 1500 20000

20

40

60

80

100

120

140

Na0.44

MnO2-Hard carbon

Discharge capacity

Sp

ec

ific

ca

pa

cit

y (

mA

h•g

-1)

Cycle number

0

20

40

60

80

100

Coulombic efficiency

1.5 to 3.8 V Co

ulo

mb

ic E

ffic

ien

cy

(%

)

2C

77% retention

over 2000 cycles

78% retention

over 2000 cycles

The effect of different voltage window to the full cell performance

0 500 1000 1500 20000

50

100

150

200

250

300

Na0.44

MnO2-Hard carbon

Discharge capacity

En

erg

y d

en

sit

y (

Wh

•kg

-1)

Cycle number

0

20

40

60

80

100

Coulombic efficiency

1.5 to 4.1V

En

erg

y E

ffic

ien

cy (

%)

2C

0 500 1000 1500 20000

50

100

150

200

250

300

Na0.44

MnO2-Hard carbon

Discharge capacity

En

erg

y d

en

sit

y (

Wh

•kg

-1)

Cycle number

0

20

40

60

80

100

Coulombic efficiency

1.5 to 3.8 V

En

erg

y E

ffic

ien

cy

(%

)

2C

~280 Wh/kg

based on active

cathode material

~250 Wh/kg

based on active

cathode material

Na0.44MnO2-Hard Carbon Full Cell

13

ii) Development of Na3V2(PO4)3 Cathode

Na3V2(PO4)3–graphene composite cathode

0 5 10 15 20 25 30 35

0

50

100

150 Na3V

2(PO

4)3-C

30% SP

20% KB

10% graphene

no carbon coating

Sp

ecif

ic c

ap

acit

y (

mA

h•g

-1)

Cycle number

0.1C0.2C

0.5C 1C2C

4C0.5C

Carbon coating is necessary to get good rate performance

The use of graphene can improve the rate performance of Na3V2(PO4)3

(1C = 120 mA/g).

14

Na3V2(PO4)3–graphene composite shows good cycling stability in half cell ~97% capacity retention over 1600 cycles at 0.5C rate (cycled for 8 months). (1C = 120 mA/g)

~63% capacity retention over 5000 cycles at 4C rate. When switch back to 0.5C rate, the capacity can be

recovered to ~85 mAh/g.

The first cycle Coulombic efficiency is ~50% at 0.1C rate.

The Coulombic efficiency at stable cycling is ~99.3% at 0.5C and ~99.9% at 4C rate.

0 5 10 15 20 25 30 500 1000 15000

20

40

60

80

100

120

140

Discharge capacity

Sp

ec

ific

ca

pa

cit

y (

mA

h•g

-1)

Cycle number

0.1C

0.5C

1C2C

0.5C0.2C

4C

Na3V

2(PO

4)3-graphene

0

20

40

60

80

100

Coulombic efficiency

Co

ulo

mb

ic E

ffic

ien

cy

(%

)

0 5 10 15 20 25 30 1000 2000 3000 4000 50000

20

40

60

80

100

120

140

Discharge capacity

Sp

ec

ific

ca

pa

cit

y (

mA

h•g

-1)

Cycle number

0.1C 4C

1C

2C

0.5C0.2C

4C

Na3V

2(PO

4)3-graphene

0

20

40

60

80

100

Coulombic efficiency

Co

ulo

mb

ic E

ffic

ien

cy

(%

)

Cycling stability of Na3V2(PO4)3 Cathode

15

Na3V2(PO4)3-hard carbon full cell can have a capacity of ~97 mAh/g at 0.25C

rate and ~80 mAh/g at 1C rate. The energy density based on active cathode

material is ~315 Wh/kg and ~250 Wh/kg, respectively.

It has good cycling stability with ~99% capacity retention over 100 cycles.

0 20 40 60 80 1000

20

40

60

80

100

120

Discharge capacity

Sp

ec

ific

ca

pa

cit

y (

mA

h•g

-1)

Cycle number

0.25C

Na3V

2(PO

4)3-hard carbon

0

50

100

150

200

250

300

350

Energy density

En

erg

y d

en

sit

y (

Wh

•kg

-1)

0 20 40 60 80 1000

20

40

60

80

100

Discharge capacity

Sp

ec

ific

ca

pa

cit

y (

mA

h•g

-1)

Cycle number

0.1C

Na3V

2(PO

4)3-hard carbon

1C

0

50

100

150

200

250

300

350

Energy density

En

erg

y d

en

sit

y (

Wh

•kg

-1)

Na3V2(PO4)3-Hard Carbon Full Cell

99% retention

99% retention

16

iii) Exploration of Prussian blue cathodes

The capacity is ~88 mAh/g at 0.1C and ~56 mAh/g at 0.5C rate (1C = 100 mA/g).

It has excellent cycling stability with the capacity retention of ~68% (38 mAh/g) over

3000 cycles. at 0.5C.

The first cycle Coulombic efficiency is ~77%. The Coulombic efficiency is ~99.8% at

stable cycling at 0.5C rate.

CuHCFe from Stanford

0 5 10 15 20 25 1000 2000 30000

20

40

60

80

100

Discharge capacity

Sp

ecif

ic c

ap

acit

y (

mA

h•g

-1)

Cycle number

0.1C

0.5C1C

2C

0.5C

0.2C

4C

Prussian blue

0 50 100 150

2.0

2.5

3.0

3.5

4.0

1st cycle

1000th

cycle

3000th

cycle

Vo

lta

ge

(V

)

Specific capacity (mAh•g-1)

17

Improvement of Cathode Coulombic Efficiency

The cathode materials’ Coulombic

efficiency, especially the first cycle

efficiency, can be greatly improved.

The Coulombic efficiency of Na0.44MnO2

is 99% after the 3rd cycle at 0.1C rate.

(1C = 120 mA/g)

The first cycle Coulombic efficiency of

Na3V2(PO4)3-graphene is ~88% at 0.1C

rate. It quickly increases to 98%. The

Coulombic efficiency can be ~99.8% at

stable cycling at 0.5C. (1C = 120 mA/g)

The first cycle Coulombic efficiency of

Prussian blue material can be ~91% at

0.2C rate. It quickly increases to 99%.

The Coulombic efficiency can be ~99.8%

at stable cycling at 1C. (1C = 120 mA/g)

0 5 10 15 20 25 40 60 80 1000

20

40

60

80

100

120

140

Discharge capacity

Sp

ec

ific

ca

pa

cit

y (

mA

h•g

-1)

Cycle number

0.1C 0.5C1C 2C0.5C

0.2C

4C

Na3V

2(PO

4)3-graphene

0

20

40

60

80

100

Coulombic efficiency

Co

ulo

mb

ic E

ffic

ien

cy

(%

)

0 5 10 15 20 25 50 1000

20

40

60

80

100

120

140

Discharge capacity

Sp

ec

ific

ca

pa

cit

y (

mA

h•g

-1)

Cycle number

0.2C

1C2C5C

1C0.5C

10C

Prussian blue

0

20

40

60

80

100

120

Coulombic efficiency

Co

ulo

mb

ic E

ffic

ien

cy

(%

)

0 20 40 60 80 1000

20

40

60

80

100

120

140

Na0.44

MnO2

Discharge capacity

Sp

ecif

ic c

ap

acit

y (

mA

h•g

-1)

Cycle number

0

20

40

60

80

100

Coulombic efficiency

2.0 to 3.7 V

Co

ulo

mb

ic E

ffic

ien

cy (

%)

1C

0 500 1000 1500 20000

20

40

60

80

100

120

140

Na0.44

MnO2

Discharge capacity

Sp

ec

ific

ca

pa

cit

y (

mA

h•g

-1)

Cycle number

0

20

40

60

80

100

Coulombic efficiency

2.0 to 4.0 V

Co

ulo

mb

ic E

ffic

ien

cy

(%

)

1C0.1C

18

Summary

Potentially low cost and scalable methods have been developed for

the synthesis of metal oxide, phosphate, and Prussian blue cathodes

for room-temperature Na-ion batteries.

The full cell of Na0.44MnO2 and commercial hard carbon has a high

capacity of ~108 mAh/g at 2C rate and excellent cycling stability with

~77% capacity retention over 2000 cycles.

The phosphate cathode has a high capacity of ~100 mAh/g at low

charge/discharge rate and excellent cycling stability with ~97%

capacity retention over 1600 cycles.

Prussian blue as a new cathode material is under exploration . A

capacity of ~100 mAh/g was obtained at 0.2C rate.

The Coulombic efficiency of cathode materials can be improved.

19

Future work

Development of stable Na-ion battery anode materials of

high capacity and high Coulombic efficiency.

Demonstration of high performance Na3V2(PO4)3 full cells

Development of Prussian blue cathode materials

Material scale up to large cell (pouch cells or 18650 cells)

fabrication

Safety (heat generation) assessments and cost estimation

(component cost).

Acknowledgements

US DOE Office of Electricity – Dr. Imre Gyuk, Energy Storage Program

Manager

A portion of the research was performed using EMSL, a national scientific

user facility sponsored by the Department of Energy's Office of Biological

and Environmental Research and located at Pacific Northwest National

Laboratory.

20