Oxide Cathodes: Functions, Instabilities, Self Healing, and Degradation Mitigations.

Area of Science:

• Materials Science
• Electrochemistry
• Solid-state Chemistry

Background:

• High-energy-density oxide cathodes enable advanced lithium-ion batteries.
• Hybrid anion- and cation-redox (HACR) mechanisms involve exotic valence states, like oxidized oxygen ions.

Purpose of the Study:

• To provide a systematic overview of oxide cathode functions, instabilities, and material behaviors.
• To elucidate the mechanisms behind degradation and self-healing phenomena.

Main Methods:

• Literature review and analysis of existing research on oxide cathodes.
• Examination of material behaviors under extreme electrochemical cycling conditions.

Main Results:

• High-voltage charging induces unusual anion and cation mobilities and exotic valences.
• Electrochemical cycling leads to lattice reconstructions, including beneficial self-healing and detrimental phase changes.
• Unique electrochemomechanical coupling effects are observed, influencing material properties.

Conclusions:

• Understanding these behaviors is critical for designing next-generation cathodes.
• Insights aid in mitigating degradation and exploiting unique properties for energy storage and catalysis.