Enhancing Anionic Redox Reversibility and Structural Stability of Li-Rich Mn-Based Cathodes via Tuning Band Structure...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Li-rich Mn-based cathodes (LRMs) offer high specific capacity via anionic redox.
• Anionic redox irreversibility causes oxygen release and Mn-ion migration, leading to capacity decay.
• Structural instability and voltage fade limit LRM performance.

Purpose of the Study:

• To enhance anionic redox reversibility and structural stability in LRMs.
• To investigate the effect of Sn doping at Mn sites on LRM performance.
• To improve cycling stability and high-rate capability of LRMs.

Main Methods:

• Density Functional Theory (DFT) calculations for electronic structure analysis.
• Synthesis and characterization of Sn-doped LRMs.
• Electrochemical performance testing (cycling stability, rate capability).

Main Results:

• Sn doping modulates energy bands, enhancing O 2p orbital overlap with (TM-O) antibonding orbitals.
• This band engineering improves anionic redox reversibility and suppresses oxygen release.
• Sn doping reduces Mn3+ content and alleviates MnO6 octahedra distortion, enhancing structural stability.
• Sn-doped LRMs exhibit superior cycling stability and high-rate performance.

Conclusions:

• Sn doping is an effective strategy for improving LRM performance.
• Energy band engineering via Sn doping enhances anionic redox reversibility and structural stability.
• This approach offers a pathway for developing high-performance LRMs for energy storage.