Mn-based Li-rich layered oxides obtained by double-surface modification engineering as high performance cathode...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-rich layered oxides (LLOs) offer high specific capacity (>250 mA h g⁻¹) for energy storage.
• However, LLOs suffer from poor cycling stability due to irreversible lattice oxygen loss and structural degradation.

Purpose of the Study:

• To enhance the multiplicity performance and cycling stability of lithium-rich manganese-based materials.
• To address the degradation issues of LLOs through surface modification techniques.

Main Methods:

• Dual surface treatment involving Li₂O-2B₂O₃ (LBO) coating and oxygen vacancy modification.
• In situ generation of a surface spinel phase via vacancy treatment.
• Characterization using XRD and Raman spectroscopy, and diffusion coefficient calculations.

Main Results:

• The dual-surface modification successfully constructed a 3D channel and formed a surface spinel phase, suppressing oxygen degradation.
• Modified Li₁·₂Mn₀·₅₄Ni₀·₁₃Co₀·₁₃O₂ (LB-M) achieved 242.8 mA h g⁻¹ after 100 cycles at 0.2 C, with 96.5% capacity retention.
• Analysis confirmed improved multiplicity performance and cycling stability.

Conclusions:

• The combined LBO coating and oxygen vacancy modification effectively improved LLO performance.
• This dual-surface engineering strategy offers a promising route for developing stable and high-performance LLO cathodes.
• The findings provide new insights into modifying Li-rich manganese-based materials for advanced batteries.