Rechargeable Dendrite-Free Zinc Anode RANGE ANNUAL REVIEW 8 9 - - PowerPoint PPT Presentation

Rechargeable Dendrite-Free Zinc Anode

RANGE ANNUAL REVIEW 8–9 January 2015

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A New Dimension in Energy

DE-AR-0000391

Principal Investigator Michael Burz, CEO, EnZinc, Inc. Technical Principal Investigator Debra Rolison, U.S. Naval Research Lab

Technology Overview Current Status

• 1. Develop a non-Li EV battery based on

NRL’s 3D Zinc sponge electrode in fully rechargeable Ni–Zn cell configuration & demonstrate dendrite-free cycling at Li- competitive depth-of-discharge (DOD)

• 2. Projected cost-competitive (<$180/kWh)

with Nissan Leaf Li-ion at 100 kg lower weight

• 1. PROVEN: dendrite-free cycling

ü >80 cycles at 40% DODZn ü

>100 start–stop duty cycles

ü 5-cm2 pouch cells running

• 2. EVALUATED: Electrolytes to enhance

ZnO precipitation

• 3. EVALUATED: for e-bike|start–stop|BEV
• 4. NEXT TECHNICAL: Scale-up to 25 cm2 @

100 cycles

• 5. NEXT COMMERCIAL: Obtain strategic

partner for commercial deployment

• 6. HELP NEEDED: Sourcing high-capacity

NiOOH cathode

Rechargeable Dendrite-Free Zinc Anode

TEAM: Michael Burz, CEO, EnZinc: mburz@enzinc.com Team Member: U.S. Naval Research Laboratory Technical PI: Debra Rolison

Project Statistics

Award Amount $452,358 Award Timeline March 2014 – March 2015 Next-Stage Target Battery Scale-up Collaborations Sought Hi-Capacity Cathode Supplier Strategic Partner Create fully metallic, highly conductive pathways in 3D

→ improve current distribution → suppress dendrite formation

3D Zn sponge

1–6 mm thick

• Tested six electrolyte compositions → two selected

Pre-cycled Zinc Sponge Post-cycled Zinc Sponge

Down-selected electrolyte composition

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thinned 1-cm2 Zn sponge disk

40% DODZn 20 mA cm–2 (160 mA g–1

Zn)

Cycling ongoing 77 cycles @ 40% DODZn 40% DODZn 5 mA cm–2 (40 mA g–1

Zn)

• Demonstrated >70 cycles of

3D Zn sponge anode versus two-ply harvested NiOOH in prototype cells (cycling terminated when capacity fades to 20% DODZn)

NRL electrolyte #1

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Dendrite-free cycling to 40% DODZn

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2.5 h 10% DODZn 4 h 15% DODZn 15 min 5 s 5 s 5 min 1 h

Constructed Duty Cycle to Evaluate Pulse Power

• Steady load of –5 mA cm–2
• Two pulses of –75 mA cm–2 for 5 s
• One pulse of –25 mA cm–2 for 15 min
• 12% DODZn, 63 W h kg–1 in packaged cell
• 109 total cycles (one month)

Step mA cm–2 C rate (anode only) C rate (packaged cell)†

–5 C/25 C/10 –25 C/5 C/2 –75 C/1.75 1.5C

† Assuming 40%

theoretical DODZn

NRL electrolyte #2

–75 mAcm–2 5 s

time (s) 100 200 300 400 discharge voltage (V) 1.4 1.5 1.6 1.7 1.8

–25 mAcm–2 15 min

Elapsed cycling time (h)

NiOOH–3D Zn: Start–stop duty cycles

Zinc Sponge Anode Delivers Performance

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E-bike Start–stop/ Microhybrid Low-range EV

SLA Ni–3D Zn AGM (Trojan 12) Ni–3D Zn Li-ion (Nissan Leaf) Ni–3D Zn Energy Capacity (Wh) 540 540 1720 1720 24000 24000 Weight (kg) 12.2 5.9 45.0 21.7 339 220 Specific Energy (Wh kg−1) 44.3 91.8 38.2 79.2 71 109 Energy Density (Wh L−1) 140 225 126 164 96 216

Zinc Sponge Anode is Cost Competitive

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100 200 300 400

Usable Stored Energy (Wh kg−1)

Low High

Price to Use ($/Wh/cycle)

Lead Acid Li-Ion 3D NiZn 3D Zn-Air

0" 50" 100" 150" 200" 250" 300" Li)Ion" Ni)3D"Zn" Average'Ba)ery'Cost'$/kWh' Margin" SG&A" Labor"&"Other"Costs" Material"

DE-AR-0000391 Dendrite-Free, Rechargeable Zinc Sponge Anode

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Mandatory and Additional Information

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Summary of Major Accomplishments

• Achieved dendrite-free cycling of 3D Zn sponges

ü >80 cycles at 40% DODZn

• Demonstrated >100 start–stop duty cycles
• Fabricated pouch cell

ü 5-cm2 Zn electrode + harvested NiOOH cathode ü Molds procured for 25-cm2 Zn electrode (seedling deliverable)

• Performance & cost analysis show Ni–3D Zn

competitive to existing lead-acid, Ni–MH, Ni–Zn & Li-ion batteries

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Lessons Learned

• Limited cell DOD arises from low-capacity NiOOH

commercial cathodes

• Obtain only ~20 DODZn% per one-ply cm2 of NiOOH

harvested from commercial AA Ni–Zn cell

• Identified electrolytes to enhance ZnO precipitation at

3D Zn surfaces

• Established protocols to incorporate 3D Zn sponges in

practical cell configurations

Collaborations sought: Technical & T2M

• Require source of high-capacity NiOOH cathode
• Provide >75 mAhcm–2 of NiOOH cathode (to match 60%

DODZn of 1-mm–thick Zn sponge)