Suppression of High Spin State of Mn for the Improvement of Mn‐Based Materials in Rechargeable Batteries

Abstract Manganese‐based materials are essential for developing safe, cost‐effective, and environmentally sustainable rechargeable batteries, which are critical for advancing clean energy technologies. However, the high spin state of the Mn cation triggers a pronounced Jahn–Teller effect and phase transformations during cycling, leading to structural instability and reduced electrochemical performance of the Mn‐based cathodes. This review provides a fundamental understanding of the Jahn–Teller effect, highlights recent strategies to mitigate the high spin state of Mn, and offers insights into future research directions aimed at overcoming the Jahn–Teller effect to enhance the performance of next‐generation Mn‐based cathodes for rechargeable batteries.