Manganese-Based Composite-Structure Cathode Materials for Sustainable Batteries

Manganese-based cathode materials have garnered extensive interest because of their high capacity, superior energy density, and tunable crystal structures. Despite their cost-effectiveness, challenges like Mn dissolution and gas evolution originating from the irreversible structural degradation pose risks to stability and prolonged electrochemical behaviors, ultimately constraining their practical applications and market prospects. While the material characteristics and redox mechanisms of Mn-based cathodes are extensively investigated, a systematic iterative approach to material design that balances performance and application demands remains both necessary and urgent. Recent strategies for enhancing cathode performances emphasize the innovative introduction and customization of composite structures in Mn-based cathode materials to address the challenges above. This review aims to provide a comprehensive understanding of composite-structure construction methodologies and offers practical guidelines for effectively designing high-stability Mn-based composite-structure cathode materials. This encompasses the classifications of composite scales, the discussions for the extent of composite-structure construction inside and outside of the cathode grains, and an exploration of the development potential of these materials, especially for grid-scale applications.