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U.S. Department of Energy

Vehicle Technologies Office Electric Vehicle Battery Research Pathways and Key Results

David Howell Brian Cunningham (Presenter)

Tien DuongPeter FaguySamuel GillardMarch 21, 2017

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Overview

• Energy Storage Funding within the Department of Energy• Vehicle Technologies Office Energy Storage Overview• Industry Cost Trends• Technologies That Can Achieve VTO’s 2022 Cost Goal• VTO Roadmap• Current Research Status• VTO R&D Highlights• Summary and Conclusions

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Fundamental research to understand, predict, and control matter and energy at electronic, atomic, and molecular levels.

JCESR (Hub) EFRC Core Scientific Research

High-risk transformational research.

BEEST (High Energy) AMPED (Battery Sensors

and Controls) RANGE (Flow, Solid

State, Multifunctional) IONICS (Solid State)

Vehicle Technologies OfficeAdvanced Research Projects Agency – EnergyOffice of Science

Grid Storage

Office of Electricity Delivery & Energy Reliability

Energy Storage R&D Interactions at DOEFundamental Research Transformational Research Applied Research

FY16:~$25M

FY16: ~$35-40M

FY16: ~$100M

FY16: ~$20M

Advanced Batteries for Vehicles

Energy Storage Funding within DOE

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VTO Energy Storage R&D Overview and Strategy

CHARTER: Develop battery technology that will enable large market penetration of electric drive vehicles

2022 GOAL: $125/kWh(useable)

Energy Storage R&D

Battery Testing, Design, & AnalysisBattery DevelopmentApplied Battery

Research (ABR)Battery Materials Research (BMR)

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VTO Energy Storage R&D Overview and Strategy

CHARTER: Develop battery technology that will enable large market penetration of electric drive vehicles

2022 GOAL: $125/kWh(useable)

Battery Manufacturing and Process Development

Energy Storage R&D

Battery Testing, Design, & Analysis

Applied Battery Research (ABR)

Battery Materials Research (BMR) Battery Development

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Production of EDV batteries doubling globally every year since 2010.

8% annual cost reductions for major manufacturers.

Economies of scale continue to push costs towards $200/kWh.

With new material chemistries and lower-cost manufacturing, cost parity with ICEs could be reached in the ten years.

“Rapidly falling costs of battery packs for electric vehicles”, B. Nykvist and M. Nilsson; Nature, Climate Change; March 2015, DOI: 10.1038/NCLIMATE2564

95% conf. interval, whole industry95% conf. interval, market leadersPublications, reports, and journals

News items with expert statementsLog fit of news, reports, and journals: 12 ± 6% decline

Additional cost estimates without a clear methodMarket leader, Nissan Motors (Leaf)

Market leader, Tesla Motors (Model S)Other battery electric vehicles

Log fit of market leaders only: 8 ± 8% declineLog fit of all estimates: 14 ± 6% decline

Future costs estimated in publications<US $150/kWh goal for commercialization

2005 2010 2015 2020 2025 2030

2,000

1,600

1,800

1,400

1,200

1,000

800

600

400

200

0

2014

US$

/kW

h2022 DOE cost target $125/kWh

DOE funded projects: 2007 –2014

2012 DOE cost target $600/kWh

2016 DOE cost $245/kWh

How are we doing?

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Cost modeling conducted on advanced battery chemistries using the ANL BatPaC2.1 model

Significant cost reductions are possible using more advanced lithium-ion materials systems– Lithium-ion: Silicon based

anode coupled with a high capacity cathode presents moderate risk pathway to battery systems for less than 125/kWhuse

– Lithium metal: A higher risk pathway to generation of systems below $100/kWhuse

These are the best case projections assuming: Elimination of chemistry problems No performance limitations Assumptions of favorable system engineering are valid Realization of high-volume manufacturing

Projected Cost (100 KWhTotal Battery Pack)

Courtesy: ANL BatPaC

What can get us there?

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Current emphasis: The development of high voltage cathodes and electrolytes coupled with high capacity metal alloy anodes. Research to enable lithium metal-Li sulfur systems.

Lithium Metal-Lithium Sulfur–Lithium AirTheoretical Energy: 3000 Wh/kg, >3,000 Wh/l

Silicon Anode with High-Voltage CathodePractical Energy: 300 – 400 Wh/kg, 800 – 1,200 Wh/l

Smaller & Lower cost EV Battery

High-Voltage CathodePractical Energy: 220 Wh/kg, 600 Wh/l

Achieved

Long Term Research

Focus 2016-20202022 DOE EERE EV Goals: $125/kWhuse

Focus 2010-20152014 DOE EERE PHEV

Goals: $300/kWhuse

~300 Cells, ~$10,000 PHEV Battery

~200 Cells, ~$3400 PHEV Battery

$125/kWhuse EV Battery(2022)

2012 2015 2020

Graphite/Layered CathodeTheoretical: 400 Wh/kg, 1,400 Wh/l

Practical Energy: 150 Wh/kg, 250 Wh/l

Ener

gy

VTO R&D Roadmap

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Current emphasis: The development of high voltage cathodes and electrolytes coupled with high capacity metal alloy anodes. Research to enable lithium metal-Li sulfur systems.

Lithium Metal-Lithium Sulfur–Lithium AirTheoretical Energy: 3000 Wh/kg, >3,000 Wh/l

Silicon Anode with High-Voltage CathodePractical Energy: 300 – 400 Wh/kg, 800 – 1,200 Wh/l

High-Voltage CathodePractical Energy: 220 Wh/kg, 600 Wh/l

Achieved

Long Term Research

Focus 2016-20202022 DOE EERE EV Goals: $125/kWhuse

Focus 2010-20152014 DOE EERE PHEV

Goals: $300/kWhuse

~300 Cells, ~$10,000 PHEV Battery

~200 Cells, ~$3400 PHEV Battery

2012 2015 2020

Graphite/Layered CathodeTheoretical: 400 Wh/kg, 1,400 Wh/l

Practical Energy: 150 Wh/kg, 250 Wh/l

Ener

gy

VTO R&D Roadmap

Fast Charge

$125/kWhuse EV Battery(2022)

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Challenges:

Limited by the cathode performance – materials changed little over 20 years and limited to 4.3V operation due to electrolyte oxidation at higher voltages

Excess Li materials show promise but are not ready for prime time due to issues with voltage fade, high impedance, and low tap density

Approach:

Understand reactivity at voltages above 4.3V and design new electrolytes, additives and inorganic coatings to “protect” the cathode

Understand phase transformation in excess Li cathodes to design better materials

Current Emphasis: Development of high Nickel NMC and mitigation of the inherent voltage fade of the Li rich layered, layered cathodes

Capacity (mAh/g)

Voltage Profiles for Li-rich, Layered Cathode

Volts

Volts

Current Research Status for Li-ion Batteries: Advanced Cathodes

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Advanced Cathodes: Recent Highlights

Developed a new class of electrolytes based on fluorinated carbonate solvents.

New electrolyte is capable of forming robust SEI on graphite anode and has reduced flammability.

Delivered LiNi0.5Mn1.5O4/graphite coin cells w/ new F-electrolyte and retained 80% capacity after 750-900 1C/1C cycles (4.7V – 3.5V).

Developed a high throughput affordable ALD coating system that can be used to coat cathode materials.

Developed 2Ah cells with ALD coated NMC 811 and graphite capable of 800-900 cycles while maintaining 80% capacity retention from 4.35V – 3V.

Promising initial results for LNMO and graphite cycled to 5V.

Developed an organosilicon material that inhibits LiPF6 breakdown.

Benefits seen with 2-5% concentrations.

Allows cells to operate at higher temperature and voltages.

Developed LCO pouch cell with 3% organosilicon material that achieved 400 1C/1C cycles from 4.45V -3V at 45C. Double the baseline cell.

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Si Nanoparticle Anode(Poor areal capacity)

Bulk Si Anode

Si NTs(Scalable approach, high areal capacity >1.5 mAh/cm2)

Si Nanotube: HRTEM

100 nm

Challenges: Large first-cycle irreversible loss Low loading/areal capacity Large capacity fade Poor coulombic efficiency Inferior rate capability

Approach: Novel architectures: Nanotubes

(NTs), Nanowires, core-shell structures, composites

Functional coatings: Metals, Li+and e- conducting ceramics, carbon based systems

Binders: High strength and elastomeric polymers

Electrolyte additives: VC, FECSource: BATT projects

Current Research Status for Li-ion Batteries: Advanced Anodes

Current Emphasis: Development of high-capacity reversible Si anode composites with good rate capability and cycle life

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Developed a 2Ah pouch cell with a novel silicon nanowire structure.

2Ah cell completed 500 DST cycles with 80% capacity retention with a beginning-of-life specific energy greater than 300Wh/kg.

Will scale up their manufacturing process to enable production of 10Ah and 40Ah cells targeting 350Wh/kg at beginning-of-life.

Advanced Anodes: Recent Highlights

Developed a unique graphene silicon composite anode that delivers high capacity (600 mAh/g), high first cycle efficiency (~85%), and >85% capacity retention at 1,000 cycles.

1,000 cycles were carried out in a prototype 2Ah pouch cell that was optimized to achieve 1,000 cycles; future efforts will focus on increased specific energy while maintaining cycle life.

Developed 18650 cells w/ their CAM-7 cathode and a silicon based anode that delivers >200Wh/kg and >85% capacity retention after 1,000 cycles.

Models predict chemistry could reach 220Wh/kg in state-of-the-art 18650 hardware and 250Wh/kg in 15Ah pouch cells designed for PHEV applications.

18650 cells are capable of >845W/kg down to 10% SOC.

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Current commercial cells capable of 200-250 Wh/kg and 1000-5000 cycles

1K

Advanced Anodes: Key Technical Results

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Summary & Conclusions

Track-record of success– American-based battery factories supplying PEV

batteries to multiple PEVs– Cost goals met or on track to be met

SEM of Li2FeSiO4/C nanospheres

SEM pictures of LiNi0.5Mn1.5O4 made from MnO2, MnCO3 and hydroxide precursors

Clear-pathway to meet 2022 goals– Major focus on advanced Lithium ion using

higher voltage cathodes & intermetallic anodes– Expanded work on low cost materials,

electrode and cell manufacturing

Technologies to go Beyond 2022– Continued focus on Li metal, sulfur electrodes

and solid state electrolytes– Closely coordinated with ARPA-E and the Office

of Science

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For More Information…

Brian Cunningham, Hybrid and Electric Systems, Vehicle Technologies OfficeU.S. Department of Energy, 202-287-5686, Brian.Cunningham@ee.doe.gov

www.vehicles.energy.gov

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Backup

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Beyond Li-ion R&D: Li Metal Anode

Opportunity Dramatic increases in specific and volumetric energies

possible

Objectives Key technical hurdle is to prevent the gradual loss of lithium

and impede dendrite formation while providing adequate power

This will be addressed through: – Improved understanding of the chemical and physical

processes that consume lithium at the electrode-electrolyte interface

– Electrolyte additives to prevent dendritic Li growth– Engineering barrier materials, solid or composite

electrolytes to stabilize the anode-electrolyte interface Evolution of an SEI Layer on Cycling of a Metallic Lithium Electrode (scale bars

represent 100 microns)

Before cycling (with SEI layer)

10 cycles

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Pristine GO film

Sparked rGO film

Li-rGOcomposite

Cross-section view

Top view: After 10 cycles, the surface is smooth without Li dendrites

Y. Cui group, Nature Nanotechnology (2016) DOI:10.1038/NNANO.2016.32

Reduced Graphene Oxide with Nanoscale Interlayer Gaps as Stable Host for Li Metal Anodes

Li Metal Anode: Recent Highlight

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Y. Cui group, Nature Nanotechnology (2016)

Cycling of Li–Reduced Graphene Oxide Electrodes

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Beyond Li-ion R&D: Sulfur Electrode

Approaches Identify basic mechanisms using in situ-EPR and

NMR studies Explore sulfide, selenide and oxide composite

electrodes showing cycling up to 300 cycles Use of lithium-ion conductor coatings and

matrices showing low fade rates (<0.003% per cycle)

Mesoscale modeling to understand polysulfide mechanisms

Specific capacity improvement by use of oxide composite electrodes upon prolonged 300 charge-discharge cycles at 0.5C

Nanoporous CFM containment and improvement in cycling stability when tested at C/6 rate

Barriers Formation/dissolution of polysulfides Sluggish kinetics of subsequent conversion of

polysulfides to Li2S High diffusivity of polysulfides in the electrolyte Insulating nature or poor conductivity of

sulfur/Li2S Volumetric expansion/contraction of sulfur

Minimum energy path for lithium ion diffusion on oxide surfaces and (f) Potential energy profiles for Li+ diffusion along different adsorption sites

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Beyond Li-ion R&D: Solid Electrolytes

Barriers Not all are stable against lithium Have relatively poor ionic conductivity at room temperatures Exhibit inherently very large interfacial impedance Brittle and difficult to fabricate

Approaches Perform mechanical studies through state-of-the-art nano-indentation techniques to

probe the surface properties of the solid electrolyte and the changes occurring to lithium Develop composite electrolytes (polymer and ceramic electrolytes) and investigate lithium

ion transport at the interface to determine the effective ionic conductivity Identify the correlation between defect types and the current density limit in Garnet-

based electrolytes Computationally and experimentally study the interfacial structure-impedance

relationship in Garnet-based electrolytes to design new materials