Synergistic regulation of low-defects manganese hexacyanoferrates with stable electrode/electrolyte interface for enhancing electrochemical potassium storage performance

Abstract

Potassium manganese hexacyanoferrate (K-MnHCF) has been considered as a promising cathode material for potassium-ion batteries (PIBs) on account of their high potential and capacity, but suffers from the poor cyclic performance. Herein, a synergistic strategy combining the defects-reducing of K-MnHCF together with the electrode/electrolyte interface-stabilizing is developed to boost the electrochemical potassium-ions storage performance. By adjusting the co-precipitation process, K-MnHCF displays the regular cubic particle with the size of 100–150 nm, exhibiting the reversable capacity of 95 mAh g−1 at 50 mA g−1 in KPF6 electrolyte system. Stabilizing the interface between K-MnHCF cathode material and electrolyte is further applied to enhance the cyclic stability and coulombic efficiency (97.6 %) of K-MnHCF cathode, by reducing the side reactions at the interface in high concentration KFSI electrolyte system. This work provides a strategy to boost the electrochemical potassium-ions storage performance of PIB cathode by synergistic stabilizing of the cathode material and the electrode/electrolyte interface.