CuCl2-Based Cathode Material with Incombustible Inorganic Liquid Electrolyte Towards Room-Temperature Na Rechargeable Battery

Abstract

Na rechargeable batteries have gained much attention as an alternative power sources of Li rechargeable batteries. Nevertheless, further advance on Na rechargeable batteries is necessary, to compete in rechargeable battery market because of their low energy density and reliability. Here, we demonstrate a new type of room temperature Na rechargeable battery which employs CuCl2/C nanocomposite cathode material and SO2-based inorganic liquid electrolyte. A high discharge capacity of 200 mAh g−1 corresponding to theoretical energy density of 580 Wh kg−1 is achieved, and also a high round-trip energy efficiency (>96%) and excellent cycle-life over 1000 cycles, which has never been obtained in conventional organic electrolyte system. The remarkable electrochemical performance is mainly attributed to the use of the non-flammable SO2-based electrolyte, which guarantees a reversible conversion reaction between CuCl2 and CuCl with NaCl. Further, detailed reaction mechanism of the new battery system will be discussed in the presentation.