Anion Storage Chemistry of Organic Cathodes for High‐Energy and High‐Power Density Divalent Metal Batteries

摘要

Abstract Multivalent batteries show promising prospects for next‐generation sustainable energy storage applications. Herein, we report a polytriphenylamine (PTPAn) composite cathode capable of highly reversible storage of tetrakis(hexafluoroisopropyloxy) borate B(hfip)4 anions in both Magnesium (Mg) and calcium (Ca) battery systems. Spectroscopic and computational studies reveal the redox reaction mechanism of the PTPAn cathode material. The Mg and Ca cells exhibit a cell voltage >3 V, a high‐power density of ∼∼3000 W kg−1 and a high‐energy density of ∼∼300 Wh kg−1, respectively. Moreover, the combination of the PTPAn cathode with a calcium‐tin (Ca−Sn) alloy anode could enable a long battery‐life of 3000 cycles with a capacity retention of 60 . The anion storage chemistry associated with dual‐ion electrochemical concept demonstrates a new feasible pathway towards high‐performance divalent ion batteries.