High-Thermal- and Air-Stability Cathode Material with Concentration-Gradient Buffer for Li-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Commercializing nickel-rich layered cathodes for lithium-ion batteries (LIBs) faces challenges in achieving high capacity alongside thermal and air stability.
• Existing cathode materials often compromise between energy density and long-term durability.

Purpose of the Study:

• To develop a novel cathode material for LIBs that overcomes the limitations of current Ni-rich layered cathodes.
• To enhance both the energy density and the thermal/air stability of LIB cathodes.

Main Methods:

• Synthesis of a surface concentration-gradient spherical particle cathode.
• The particle composition varies from LiNi_1/3Co_1/3Mn_1/3O₂ (NCM) at the surface to LiNi_0.8Co_0.15Al_0.05O₂ (NCA) in the core.
• Electrochemical performance testing, including cycling stability and thermal/air stability assessments.

Main Results:

• The developed cathode material demonstrated high capacity retention of 99.8% after 200 cycles at 0.5 C.
• Significantly improved thermal and air stability compared to bare NCA (Nickel Cobalt Aluminum Oxide) was observed.
• The NCM surface layer acts as a protective buffer for the inner NCA core.

Conclusions:

• The concentration-gradient spherical particle design offers a promising strategy for high-performance LIB cathodes.
• This approach enhances energy density, cycle life, and storage stability, crucial for future LIB commercialization.
• The findings provide valuable insights for designing next-generation LIB cathode materials.