Modulation of Local Charge Distribution Stabilized the Anionic Redox Process in Mn-Based P2-Type Layered Oxides

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Anionic redox reactions offer high-energy-density cathode materials for sodium-ion batteries (SIBs).
• Inactive element doping can activate oxygen (O) redox activity in layered cathodes.
• Challenges include structural instability, voltage hysteresis, and oxygen loss during anionic redox.

Purpose of the Study:

• To investigate the impact of Li doping on oxygen charge transfer in Mn-based oxides for SIBs.
• To develop a strategy to overcome charge trapping and improve anionic redox stability.
• To provide a theoretical framework for enhancing electrochemical performance in similar systems.

Main Methods:

• Theoretical calculations and experimental studies were employed.
• Li doping was introduced into Mn-based oxide cathode materials.
• Zn²⁺ codoping was investigated as a strategy to mitigate issues caused by Li doping.

Main Results:

• Li doping creates local charge traps, hindering oxygen charge transfer and stability.
• Zn²⁺ codoping releases charge around Li⁺, distributing it onto Mn and O atoms.
• This redistribution reduces oxygen overoxidation, enhances structural stability, and improves phase transition reversibility.

Conclusions:

• Zn²⁺ codoping effectively stabilizes anionic redox reactions in Li-doped Mn-based oxides.
• The strategy improves electrochemical performance by enhancing structural integrity and reversibility.
• This work offers insights into anionic redox activation mechanisms and provides a framework for designing advanced SIB cathodes.