Enabling uniform lithiation in solid-state synthesis by preventing pre-matured surface grain coarsening through grain...

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Solid-state calcination impacts lithium-ion battery cathode performance.
• High temperatures can cause structural non-uniformity due to phase transitions.

Purpose of the Study:

• Investigate heterogeneity in early-stage solid-state lithiation.
• Understand grain formation and merging in LiNi0.9Co0.05Mn0.05 (NCM90) secondary particles.
• Develop strategies for mitigating structural non-uniformity.

Main Methods:

• Utilized operando characterization techniques.
• Employed high-resolution electron microscopy.
• Applied atomic layer deposition of WO3.

Main Results:

• WO3 coating forms stable Li_xWO_y at grain boundaries during in situ lithiation.
• Li_xWO_y acts as a segregation layer, preventing grain merging.
• Preserved uniform lithiation pathways within secondary particles.

Conclusions:

• Solid-state reaction heterogeneity affects cathode performance.
• Grain boundary engineering using WO3 coatings is a novel mitigation strategy.
• This approach enhances structural integrity and electrochemical performance.