Mitigating First-Cycle Capacity Losses in NMC811 via Lithicone Layers Grown by Molecular Layer Deposition

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Nickel-rich lithium nickel manganese cobalt oxide (NMC811) is a leading cathode material for high-energy-density lithium-ion batteries.
• Capacity fade is a critical issue limiting the long-term performance of NMC811-based batteries.

Purpose of the Study:

• To investigate the efficacy of lithicone coatings in mitigating capacity losses in NMC811 cathode materials.
• To evaluate the impact of these coatings on the rate capability and cycling stability of automotive lithium-ion batteries.

Main Methods:

• Molecular layer deposition (MLD) was used to grow lithicone layers directly onto porous NMC811 electrode particles.
• Stoichiometry of the lithicone layer (LiOC0.5H0.3) was determined using elastic recoil detection analysis.
• Nominal thickness of the lithicone layer was measured as 20 nm via ellipsometry on a reference substrate.

Main Results:

• Lithicone coatings improved the overall capacity of balanced NMC811||graphite cells by approximately 5%.
• The coatings did not adversely affect the rate capability of the batteries.
• Long-term cycling stability of the cells remained unaffected by the lithicone layers.

Conclusions:

• Lithicone coatings applied via MLD are an effective strategy to enhance the performance and durability of NMC811 cathodes.
• This approach offers a promising solution for improving the energy density and lifespan of automotive lithium-ion batteries.