High Energy High Power Battery Exceeding PHEV-40 … a blended Si/hard carbon anode with >1000mAh/cc will allow us to meet pulse power targets, while exceeding energy density of graphite

TIAX LLC 35 Hartwell Avenue

Lexington, MA 02421

Tel 781-879-1200 Fax 781-879-1201 www.TIAXLLC.com

© 2014 TIAX LLC

This presentation does not contain any proprietary, confidential, or otherwise restricted information.

Project ID# ES209

Dr. Jane Rempel (PI) TIAX LLC. June 18th, 2014 2014 DOE VTP Merit Review

High Energy High Power Battery Exceeding PHEV-40 Requirements

2 ES209: High Energy High Power Battery

TIAX is working to develop a lithium-ion battery system that meets and exceeds the PHEV-40 performance and life goals.

Timeline ♦ Project start date: October 1st, 2013

♦ Project end date: September 30th, 2015

♦ Percent complete: 25% (time)

♦ Percent complete: 18% (budget)

Budget ♦ Total project funding: $2,184,733

♦ DOE share: $1,747,787

♦ Contractor share: $436,946

♦ Funding received in FY13: $118,534

♦ Funding for FY14: $1,107,410

Barriers ♦ Gravimetric and volumetric energy density

♦ Gravimetric and volumetric power density

♦ Cycle life and calendar life

♦ Temperature range

Partners ♦ Multiple materials suppliers

Overview


TIAX is working to develop a lithium-ion battery system that meets and exceeds the PHEV-40 performance and life goals.

♦ Implement CAM-7TM/Si anode chemistry in Li-ion cells designed to achieve >200Wh/kg and >400Wh/L energy and >800W/kg and >1600W/L 10s pulse power targets under USABC PHEV battery testing procedures. − Optimize electrode designs in coin cells to demonstrate that electrodes composed of

blended Si/carbon anode opposite CAM-7TM cathode can achieve all PHEV-40 scaled-power targets.

− Select anode binder and formulate electrolyte additives that facilitate achievement of PHEV-40 cycle life target in cells implementing Si-based anode and CAM-7TM cathode.

♦ Demonstrate that these Li-ion cells have higher energy and power capability than the

baseline cell design, and deliver these cells to DOE for independent performance verification.

♦ Demonstrate that these Li-ion cells have cycle life and calendar life that project to meeting PHEV-40 targets.

Objectives/Relevance


Milestone Status

Down-select silicon active material and inactive materials and formulations Scheduled

Down-select cathode formulation and implement cathode active material synthesis scale-up Scheduled

Optimize electrode design in coin cells and select separator, electrolyte, cathode and anode formulations Scheduled

Finalize design of high capacity cells Scheduled

Fabricate demonstration cells for delivery to DOE Scheduled

Confirm performance and cycle life of Li-ion cells Scheduled

Milestones


CAM-7TM High Energy High Power Cathode ♦ Active material ideally suited for PHEV performance and life targets ♦ Electrodes optimized for energy and power density

Blended Si/Carbon Anode ♦ Si-based materials – provide high energy, with state-of-the-art materials sourced

from leading suppliers ♦ Hard carbon – excellent power-delivery but lower volumetric capacity ♦ Blend and electrode formulations optimized for energy, power, and life

Cell Design ♦ High performance separators ♦ Life-extending electrolyte additives and binders

We will employ an iterative system-level approach to cell design to develop Li-ion cells that will exceed the PHEV-40 performance and life goals.

Technical Approach


CAM-7 can deliver >200 mAh/g at rates below C/5 and 120 mAh/g at 100C discharge making it attractive for vehicle applications.

85:10:5, active:cc:PVdF, low-loading electrode, Li metal anode, 1.0 M LiPF6 in 1:1:1 EC:DMC:EMC + 1%VC electrolyte

2.9

3.1

3.3

3.5

3.7

3.9

4.1

4.3

4.5

0 40 80 120 160 200 240Specific Capacity (mAh/g)

Volta

ge (V

)

C/201C5C10C30 C50 C100 C

♦ CAM-7 is a stabilized, high-nickel cathode material that combines high energy content with high power capability

♦ Now in various stages of sampling at major companies in Korea and Japan for both portable electronics and vehicle applications

♦ CAM-7 has been evaluated in high energy and high power cell designs both at TIAX and by other companies

Discharge in Half Cells

1μm

2μm

Technical Approach: CAM-7TM Cathode

FIB/TEM SEM


TIAX’s cell prototyping facility is facilitating material evaluation and implementation.

♦Flexibility in cell formats:

−Cylindrical

−Wound prismatic

−Stacked prismatic

♦Cell capacities:

−1 – 4 Ah cylindrical

−2 - 10 Ah prismatic cells



2.5

2.7

2.9

3.1

3.3

3.5

3.7

3.9

4.1

4.3

0.0 0.5 1.0 1.5 2.0 2.5 3.0Capacity (Ah)

Volta

ge (V

)

C/20 Capacity (Ah) 2.71 C/20 Energy (Wh) 9.94 Specific Energy (Wh/kg) standard hardware 234

Specific Energy (Wh/kg) improved hardware 247

Energy Density (Wh/L) 610


These cells have a measured energy density >300 Wh/kg,

without packaging.

We have implemented CAM-7 in high energy 18650 cells with graphite anodes that can deliver 2.7Ah and 247Wh/kg.

CAM-7/Graphite 18650 Cells Fabricated at TIAX

Cathode – CAM-7:AB:PVDF (97:1:2), 25.6mg/cm², 3.64g/cc Anode – Graphite:SBR+CMC (96:0:4), 16.3mg/cm², 1.74g/cc

Cell performance was verified in independent

testing at ARL


0102030405060708090

100110

0 50 100 150 200 250

Cycle Number

Cap

acity

Ret

entio

n %

cell 1cell 2

Technical Approach: CAM-7TM Cathode CAM-7/Graphite high energy 18650 cells show stable capacity cycling at room temperature.

2.7Ah 18650 Cells – RT Cycling

100% = 2.5Ah C/2 capacity at RT

C/2

C/20 C/5

C/5 charge – C/2 discharge, 4.2 to 2.7V; C/20 & C/5 discharge every 50 cycles.


0102030405060708090

100

0 100 200 300 400 500 600 700 800Cycle Number

Cap

acity

Ret

entio

n %

cell 1cell 2

CAM-7 has been tested in higher power 18650 cells, demonstrating stable capacity cycling at room temperature and at 45°C over the full DOD range.


18650 cell with CAM-7/Graphite fabricated at TIAX. C/2 charge – 1C discharge, 4.2 to 2.7V; C/20 & C/5 discharge every 50 cycles.

1.9Ah CAM-7 18650 Cells – 45°C Cycling

100% = 1.94Ah 1C capacity at 45°C


Using a blended Si/hard carbon anode will allow us to design cells capable of delivering high energy during EV operation and high power during HEV mode of the battery.

Distance/time

Cel

l SO

C

Pulse power during EV mode met by CAM-7 and both silicon and hard carbon

Pulse power during HEV mode met by CAM-7 and hard carbon

PHEV-40 Cell SOC Change

Silicon to provide high capacity while hard carbon will meet discharge and regen power targets

Technical Approach: Blended Si/Carbon Anode


100%

105%

110%

115%

120%

125%

130%

135%

140%

145%

150%

155%

160%

165%

600 800 1000 1200 1400 1600 1800 2000 2200

Impr

ovem

ent o

ffere

d by

Si-a

node

ove

r gra

phite

ano

de 90% 1st cycle efficiency80% 1st cycle efficiency

Si maximum theoretical capacity

2190 mAh/cc

Using a blended Si/hard carbon anode with >1000mAh/cc will allow us to meet pulse power targets, while exceeding energy density of graphite cells.

Calculated Cell Level Energy Density of Si vs. Graphite Cells

Volumetric capacity of high-energy graphite electrodes

Lithiated Si anode volumetric capacity (mAh/cc)

Target of our work

Technical Approach: Blended Si/Carbon Anode

Rel

ativ

e En

ergy

of S

i vs.

Gra

phite

Cel

ls

Fixed active material volume/electrode area design; CAM-7 cathode.


0

500

1000

1500

2000

2500

3000

3500

4000

0 5 10 15 20 25 30 35 40 45 50

Cycle Number

Del

ithia

tion

Cap

acity

(mA

h/g

activ

e)

Binder selection and electrolyte formulation can significantly impact silicon based anodes and we will optimize these components to achieve life targets.

Effect of Binder on Cycle Life of Silicon Half Cells

Nano-Silicon:Conductive Carbon:Binder. Lithiation to 5mV; delithiation to 1.5V; Electrodes pressed to ~0.75g/cc; 1M LiPF6 electrolyte in 1:1:1 EC:DMC:EMC + 1%VC + 5%FEC

Technical Approach: Cell Design


Optimizing cell designs with components that facilitate increased loading will allow us to further boost the cell level energy density.

100%

110%

120%

130%

140%

150%

160%

2.00mAh/cm²

2.50mAh/cm²

3.00mAh/cm²

3.50mAh/cm²

4.00mAh/cm²

Rel

ativ

e E

nerg

y

Relative Wh/kgRelative Wh/L

Estimated relative specific energy and energy density for CAM-7/Blended Si as a function of electrode loading level.


Typical PHEV Design

Typical EV Design

Electrode Loading

Rel

ativ

e C

ell-L

evel

Ene

rgy

Maximum loading is limited by electrolyte transport and

cell power/energy performance requirements


Inactive component selection plays a crucial role in achieving power, usable energy, and life targets.

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 20 40 60 80 100SOC (%)

Pow

er (W

/cm

²)

High Power Separator

Low Power Separator

10s Discharge 10s Charge

Choice of a non-optimized separator

results in substantially larger and heavier

batteries

We have identified high power separators that support high power pulse capability over a broad SOC window.

CAM-7/Li half cells, continuous discharge from 4.3V. 1.5mAh/cm²

10s charge and discharge constant power pulse. CAM-7/Graphite, 3.5mAh/cm².


0

40

80

120

160

200

0 5 10 15 20 25 30Discharge C-Rate

Spec

ific

Cap

acity

(mA

h/g)

s5s0s3s6s7s4s2S1

Continuous Discharge Pulse Power


Cathode development work is focused on further improving high temperature cycle life of CAM-7.

Accomplishments and Progress: Cathode

♦ Improve high temperature capacity retention and reduce impedance growth. ♦ Explore cathode surface coating and test compositional changes to the bulk. ♦ Develop accelerated testing protocols to rapidly screen material modifications.

CAM-7/Graphite cells, ~2mAh/cm² loading. 1C/1C characterization cycles at 45C between 4.2V and 2.7V.

Rate of Impedance Growth at 45°C

Cycle Coating Comp 1 Coating Comp 2

CV Charge Time at 45°C

0

10

20

30

40

50

60

70

0 20 40 60 80 100 120 140

CV

Tim

e (m

in)

Dopants None A B A+B

Co Bulk

Doping

No Co Bulk

Doping

Control Coating Comp 1 Coating Comp 2 Control


We have started testing commercial Si-based materials that show promising volumetric capacity and capacity retention.

Si anode materials ♦ Source several state-of-the-art silicon anode materials. ♦ Evaluate materials for capacity, cycle life, and columbic efficiency in Li-metal

coin cells. Inactive materials ♦ Identify binders and electrolyte additives that improve cycle life and coulombic

efficiency of the Si anodes.

Accomplishments and Progress: Anode

0.0

0.3

0.5

0.8

1.0

1.3

1.5

1.8

2.0

0 300 600 900 1200 1500 1800Specific Capacity (mAh/g electrode)

Vol

tage

(V v

s. L

i)

572 mA/g287 mA/g

114 mA/g57 mA/g

Si-based Anode – Rate

0

200

400

600

800

1000

1200

1400

1600

0 10 20 30 40 50

Cycle Number

Cap

acity

(mA

h/cc

)

Si-based Anode – Cycling

150mA/g, 5mV – 1.2V

750mA/g, 50mV – 1.2V

CCCV lithiation, CC delithiation 2mAh/cm² loading, ~1g/cc


2.8

3.0

3.2

3.4

3.6

3.8

4.0

4.2

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0Specific Capacity (Ah)

Volta

ge (V

)

90 mA360 mA900 mA

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

0 200 400 600 800 1000

Current (mA)

Dis

char

ge C

apac

ity (A

h)

Baseline CAM-7/graphite cells for independent testing have been fabricated.

♦ CAM-7 cathode / graphite anode

♦ Carbonate electrolyte

♦ 18650 design – 1.9Ah

♦ Cell testing is ongoing

Program Overview Cell Design

0

20

40

60

80

100

120

140

0 20 40 60 80 100State of Charge (%)

DC

R (m

Ω)

1s10s

Discharge Capacity

Rate Capability DCR vs. SOC Data for 6 cells


TIAX has a strong working relationship with our materials suppliers.

Active Material Suppliers

♦ Si based materials – domestic and international suppliers are providing us state-of-the-art Si and Si-based composites.

♦ Carbon anodes – domestic and international suppliers of graphite and hard carbon.

Inactive Materials Suppliers

♦ Electrolytes – access to high purity electrolytes with additives specifically formulated for Si-based anodes.

♦ Separators – access to production and research grade high performance separators ideal for energy and power applications.

Collaboration and Coordination


♦ Evaluation of approaches to further improve high temperature cycle life of CAM-7 cathode.

♦ Screening of Si-based active materials from several domestic and international suppliers.

♦ Identification of inactive components to improve cycle life of Si-based materials.

♦ Design, assembly, and testing of baseline 18650 CAM-7/Graphite Li-ion cells.

Summary Work in this project to date has focused on:


♦ Continue cathode materials development to improve high temperature cycle life.

♦ Down-select cathode formulation for full cell optimization.

♦ Continue screening Si-based anode materials and evaluate blended anodes.

♦ Optimize cathode and anode electrode designs to meet power and energy targets.

♦ Screen and optimize electrolyte additives to increase cycle life.

♦ Fabricate and optimize demonstration cells.

Future Work

Documents

High Energy High Power Battery Exceeding PHEV-40 … a blended Si/hard carbon anode with >1000mAh/cc will allow us to meet pulse power targets, while exceeding energy density of graphite