Nonaqueous Electrolyte Rechargeable Manganese Batteries with Potassium Manganese Hexacyanoferrate Cathodes

Manganese batteries garnered significant attention as sustainable and cost-effective alternatives to lithium-ion batteries. For the first time, manganese batteries are demonstrated using a manganese hexacyanoferrate cathode and organic electrolyte solution, specifically saturated Mn(ClO₄)₂ in acetonitrile. The manganese hexacyanoferrate cathode exhibits an average operating voltage of 1.7 V and a discharge capacity of 73.4 mAh g^-1 at 0.1 A g^-1, retaining 71.1% capacity after 1500 cycles at 0.2 A g^-1. Diffusion pathways and barriers reveal efficient 3D Mn²⁺ ion diffusion pathways within the manganese hexacyanoferrate framework, with a low migration barrier of 0.514 eV. Despite the promising performance, surface analysis of the Mn metal anode reveals the formation of complex organic/inorganic SEI (solid electrolyte interphase) layers, including MnO_x, MnCl_x, and organic compounds, due to electrolyte decomposition. These findings highlight the critical importance of SEI layer control and electrolyte optimization for enhancing the durability and efficiency of organic electrolyte-based manganese batteries. Manganese batteries are established as a viable next-generation energy storage solution and provide a foundation for further advancements in organic electrolyte-based battery systems.