Dissolution-Equilibrium-Driven Synthesis of High-Quality K2Mn[Fe(CN)6] Cathode for High-Energy Potassium-Ion Batteries

Abstract

Prussian blue analogues (PBAs), particularly high-energy K₂Mn[Fe(CN)₆] (MnPBA), are considered ideal candidates for cathodes of potassium-ion batteries (PIBs). However, conventional coprecipitation synthesis introduces uncontrollable structural defects, including [Fe(CN)₆]^4– vacancies and lattice water. These defects result from rapid crystal nucleation and growth, which leads to a significant deterioration in electrochemical performance. In this work, we propose a dissolution-equilibrium-driven synthesis strategy that effectively controls crystallization kinetics to synthesize high-quality MnPBA with minimal defects. This work offers a simple and controllable synthesis strategy for high-quality PBAs and emphasizes the importance of minimal defects in the improvement of the electrochemical performance of PBA cathodes.