Suppressing Second-Order Jahn-Teller Distortion in VO₂(B): A Dissolution-Resistant Electrode for Durable Aqueous...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous energy storage systems require robust electrode materials.
• Vanadium oxides (VOx), especially VO2(B), show promise due to redox activity but suffer from dissolution.
• Dissolution stems from Jahn-Teller distortions and water reactions, leading to capacitance fading.

Purpose of the Study:

• To enhance the stability and performance of VO2(B) electrodes in aqueous systems.
• To mitigate dissolution issues in vanadium oxide electrodes through surface modification.

Main Methods:

• Poly-anionic group modification using phosphate groups on VO2(B) electrodes (PM-VO).
• Investigated the structural integrity of VO6 octahedra during redox cycling.
• Evaluated electrochemical performance, focusing on cycling stability and capacitance retention.

Main Results:

• Phosphate modification stabilized VO6 octahedra, reducing Jahn-Teller distortions and mitigating dissolution.
• PM-VO electrodes demonstrated significantly improved cycling stability.
• Retained 83.6% of initial capacitance after 20,000 cycles at 20 mA cm-2.

Conclusions:

• Phosphate surface engineering effectively enhances the robustness of VO2(B) electrodes.
• This strategy provides a pathway for developing stable transition metal oxide electrodes for aqueous batteries.
• The PM-VO electrode represents a promising advancement in aqueous energy storage technology.