Suppressing Jahn–Teller Distortion in Manganese Oxides for High-Performance Aqueous Zinc-Ion Batteries

Manganese oxides (MnOx) have been confirmed as the most promising candidates for aqueous zinc-ion batteries (AZIBs) due to their cost-effectiveness, high theoretical capacity, high voltage platforms, and environmental friendliness. However, in practical applications, AZIBs are hindered by the Jahn–Teller distortion (JTD) effect, primarily induced by Mn3+ (t2g3eg1) in octahedral coordination, which leads to severe structural deformation, rapid capacity fading, and poor cycling stability. This review systematically outlines the fundamental mechanisms of JTD in MnOx cathodes, including electronic structure changes, lattice distortions, and their side effects on Zn2+ storage performance. Furthermore, we critically discuss advanced strategies to suppress JTD, such as cation/anion doping, interlayer engineering, surface/interface modification, and electrolyte optimization, aimed at enhancing both structural stability and electrochemical performance. Finally, we propose future research directions, such as in situ characterization, machine learning-guided material design, and multifunctional interfacial engineering, to guide the design of high-performance MnOx hosts for next-generation AZIBs. This review may provide a promising guideline for overcoming JTD challenges and advancing MnOx-based energy storage systems.