Self‐Formulated Na‐Based Dual‐Ion Battery Using Nonflammable SO2‐Based Inorganic Liquid Electrolyte

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 17; no. 9; pp. e1902144 - n/a
• Main Authors: Kim, Ayoung, Jung, Hojae, Song, Juhye, Lee, Jiwhan, Jeong, Goojin, Kim, Young‐Jun, Kim, Hansu
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.03.2021
• Subjects: Anodes; Batteries; Cathodes; Copper chloride; discharged state cathodes; Electrode materials; Electrolytes; inorganic electrolytes; Lithium; Lithium batteries; Nanotechnology; nonmetallic anodes; Power sources; Rechargeable batteries; Sodium; sodium batteries; Storage batteries
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201902144

Sodium secondary batteries have gained much attention as alternative power sources to replace lithium secondary batteries. However, some technical issues must be solved to ensure their success. Here, a highly safe and cost‐effective Na‐based dual‐ion battery system employing self‐formulated CuCl cathode material starting from a mixture of Cu and NaCl in conjunction with a nonflammable NaAlCl4·2SO2 inorganic liquid electrolyte is demonstrated. It is found that CuCl is spontaneously formed by redox coupling of Cu/Cu(I) and SO2/SO2− anion radical. In the proposed battery, Na+ and Cl− are employed as energy carriers for the anode and cathode, respectively, and it is further demonstrated that the Na‐metal‐free battery configuration is possible using a hard carbon anode. Owing to the use of cheap electrode materials and a highly conductive and safe electrolyte, the proposed batteries deserve to be regarded as a promising approach for next‐generation Na rechargeable batteries. Na‐metal‐free dual‐ion battery systems using a self‐formulating route for CuCl cathode materials with nonflammable SO2‐based inorganic electrolyte are presented here. The discharged state active CuCl cathode materials are prepared from highly safe and cost‐effective Cu and NaCl in conjunction with a nonflammable SO2‐based inorganic liquid electrolyte.