Leveraging Reversible Chemistry for Materials Sustainability

in Energy Storage

Zheng Chen, Ph.D.
Assistant Professor, Department of NanoEngineering/Chemical Engineering
Sustainable Power and Energy Center (SPEC)
University of California, San Diego
E-mail: zhengchen@eng.ucsd.edu

Feb 16, 2021

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Materials Science and Chemical Technology for Sustainable Energy➢ Battery Safety Technology

Mechanistic
Understanding

Anode

Cycling & Degradation

SEI layer
Electrolyte

High Energy
AnodeHigh Energy Cathode

Process Design& Intensification• High Performance• Safe, Low-Cost• Recyclable

Cathode/SSEInterface

Chemical Synthesis& Conversion

Anode/SSE
Interface

Characterization & Regeneration

Materials Design& Synthesis

Cell Design➢ Design Batteries
CathodeSeparator➢ Solid-State Batteries< 50um➢ Low-Temperature Batteries

Prefabrication & Optimization
Confidential Slides – For Internal Discussion Only

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Critical Materials Are Heavily Used in Li-ion Batteries

Carbon black

Graphite(Anode)

LiMO2(Cathode)

Cathode Materials:••••

LiFePO4
LiMn2O4
LiCoO2
LixNiyMnzCo1-y-zO2(NMC111, NMC532…)• LiNi0.8Co0.15Al0.05O2

Anode Materials:• Graphite, Si..
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The lithium-ion battery life cycle report 2021

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Global Projections of Critical Materials Reserves vs Current DemandZ. Chen, et al, MRS Energy & Sustain., 2020, DOI: 10.1557/mre.2020.31.

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Li-Ion Battery Recycling Principles

Ease of Recycling

Better Labelling
9The “Direct” Recycling Process

Pouch cell

Cathode and anode strips• claim embedded energy• Reduce chemical usage
Cycled activeparticles

Regeneration• Composition recovery• Structure recovery

New active particles
10Y. Shi, Z. Chen* et al, Green Chemistry, 2018, 20, 851-862.

The “Direct” Recycling Process

Pouch cell

Cathode and anode strips• claim embedded energy• Reduce chemical usage
Cycled activeparticles

Regeneration• Composition recovery• Structure recovery

New active particles
15Y. Shi, Z. Chen* et al, Green Chemistry, 2018, 20, 851-862.

The Direct Regeneration Process18Morphological and Composition Change: the LCO Case

Hydrothermal

No annealing

700 °C 4 h

800 °C 4 hComposition

Li0.98CoO2

Li0.98CoO2

Li0.98CoO2Solid-state synthesis

750 °C 12 h

850 °C 12 h

950 °C 12 hComposition

Li0.99CoO2

Li0.98CoO2

Li0.96CoO220

Exploring the LCO Regeneration Conditions

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Recovery of Complicated NMC25

Regeneration of LiNixMnyCozO2 (NMC)
Sample

NCM111

NCM523

Pristine

Li0.995Ni0.331Co0.341Mn0.329O2.012

Li1.009Ni0.492Co0.209Mn0.305O2.015

Cycled

Li0.786Ni0.328Co0.340Mn0.325O1.996

Li0.788Ni0.490Co0.208Mn0.302O1.985

Hydro only

Li1.012Ni0.329Co0.341Mn0.326O2.009

Li1.006Ni0.491Co0.209Mn0.304O2.012

Hydro+850 ℃ 4 h

Li1.019Ni0.330Co0.340Mn0.327O2.011

Li1.021Ni0.490Co0.209Mn0.303O2.013

850 ℃ 12 h air

Li1.016Ni0.331Co0.340Mn0.325O2.010

Li1.017Ni0.490Co0.207Mn0.304O2.014

850 ℃ 12 h oxygen

Li1.016Ni0.331Co0.341Mn0.326O2.012

Li1.018Ni0.491Co0.208Mn0.304O2.013
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Regeneration of Mixed Cathodes

LCO-NCM mixed: materials mixed in the same cell
LCO+NCM mixed: cells with different materials and then mixed
Y. Shi, Z Chen, et al, ACS Energy Lett., 2018, 3, 1683.

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Ambient Pressure Re-lithiation in Eutectic Mixtures

Relithiation of 50% degraded NCM

S. Yang, Z. Chen .et al, Adv. Energy. Mater, 2019, 9, 1900454.

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EC Data for Regeneration of NCM523

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Direct Recycling of LiFePO439

Performance of Reg. LiFePO4

Z. Chen, et al, 2020, Joule,
doi.org/10.1016/j.joule.2020.10.008.
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Diatomite: A Great Resource

United States Geological Survey

50Diatomite-Derived Si AnodeZ. Chen, et al, Adv. Funct. Mater., 2020, 30, 2005956.

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Stable Cycling52

Materials Science and Chemical Technology for Sustainable Energy

Solar Cells Electronics
Batteries

Design for Recycling

Newmaterials❖ Mechanistic
Understanding

Nanoscale Defects
Characterization

GreenRegeneration❖ Materials Design& Synthesis• Structure➢Safety• Composition ➢Performance• Manufacturing ➢Cost

Fadedmaterials❖ Chemical Synthesis& Conversion
Collaborators:❖ Process Design &Intensification

Ping Liu
Shirley Meng
ShyuePing Ong
Darren Lipomi
Mei Cai@ GM

http://zhengchen.eng.ucsd.edu

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Funding: DOE, NSF, private companies.

Thank you!

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