Electrochemical Performance of Sb₄O₅Cl₂ as a New Anode Material in Aqueous Chloride-Ion Battery

Chloride-ion battery is considered as the promising electrochemical system due to its high energy density in theory. However, aqueous chloride-ion redox materials are limitedly reported owing to their instability or dissolution in aqueous electrolyte. Here, we synthetize a new electrochemical chloride-ion material, Sb₄O₅Cl₂, investigate its electrochemical performance in aqueous NaCl electrolyte, and assemble into aqueous chloride-ion battery with silver as cathode. During the battery charge process, Sb₄O₅Cl₂ anode electrochemically releases chloride ions, which are captured by Ag cathode with the formation of silver chloride while the discharging reverses the process. The battery demonstrates favorable electrochemical performance. With current density of 600 mA g^-1, the battery discharge capacity of 34.6 mAh g^-1 can be maintained for 50 cycles. This work is greatly significant for the development of anion electrochemical energy storage.