Ammonia Concentration-Directed Preferential Growth Enhancing Lithium-Ion Diffusion in Li-Rich Mn-Based Oxide Cathodes

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Lithium-rich manganese-based oxides (LRMO) are promising cathode materials for advanced batteries.
• Controlling precursor structure is crucial for optimizing LRMO electrochemical performance.
• Ammonia concentration is identified as a key factor in precursor synthesis.

Purpose of the Study:

• To investigate the influence of ammonia concentration on LRMO precursor structure and morphology.
• To understand how precursor characteristics affect the final LRMO material's properties.
• To establish a synthesis strategy for enhanced LRMO cathode performance.

Main Methods:

• Coprecipitation synthesis of LRMO precursors at varying ammonia concentrations.
• Structural and morphological characterization of precursors and final LRMO materials.
• Electrochemical performance testing (capacity, rate capability, cycling stability).

Main Results:

• Ammonia concentration significantly impacts crystallite growth and particle agglomeration.
• Optimized ammonia concentration leads to preferential (012) crystallographic growth in Mn$_{0.675}$Co$_{0.1625}$Ni$_{0.1625}$CO$_{3}$ precursors.
• The resulting LRMO material shows enhanced Li+ diffusion, higher capacity, better rate performance, and improved cycling stability.

Conclusions:

• Ammonia concentration is a critical "structure-directing factor" in LRMO precursor synthesis.
• Precise control over precursor crystallization and microstructure enhances LRMO electrochemical properties.
• This study provides mechanistic insights and a practical strategy for developing high-performance LRMO cathodes.