Manganese hexacyanoferrate reinforced by PEDOT coating toward high-rate and long-life sodium-ion battery cathode
Prussian blue analogues hold great promise as cathodes in sodium ion batteries. Among Prussian blue analogues, manganese hexacyanoferrate is desirable because of its high working voltage, as well as its high specific capacity and low cost. However, poor cycling stability and unsatisfied rate capability of manganese hexacyanoferrate, which are mainly caused by poor intrinsic conductivity, phase transition, side reactions and transition metal dissolution, extremely limits its practical application. In this work, we demonstrate a high-rate and long-life MnHCF@PEDOT sodium ion battery cathode through a facile in-situ polymerization method. Benefitting from the synergistic effect of the inhibited Mn/Fe dissolution, suppressed phase transition and improved capacitive storage, the composite electrode exhibits a high capacity of 147.9 mAh g-1 at 0.1 C, 95.2 mAh g-1 at a high rate of 10 C and 78.2% capacity retention after 1000 cycles. Furthermore, even at a low temperature of -10 °C, MnHCF@PEDOT still delivers a high capacity of 87.0 mAh g-1 and remains 71.5 mAh g-1 (82.2 %) after 500 cycles.