Self-Formulated Na-Based Dual-Ion Battery Using Nonflammable SO 2 -Based Inorganic Liquid Electrolyte

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 17; no. 9; p. e1902144
• Main Authors: Kim, Ayoung, Jung, Hojae, Song, Juhye, Lee, Jiwhan, Jeong, Goojin, Kim, Young-Jun, Kim, Hansu
• Format: Journal Article
• Language: English
• Published: Germany 01.03.2021
• Subjects: copper chloride; sodium batteries; inorganic electrolytes; discharged state cathodes; nonmetallic anodes
• 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 NaAlCl ·2SO inorganic liquid electrolyte is demonstrated. It is found that CuCl is spontaneously formed by redox coupling of Cu/Cu(I) and SO /SO 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.