Boosting Sodium Compensation Efficiency via a CNT/MnO2 Catalyst toward High-Performance Na-Ion Batteries

• Published in: ACS applied materials & interfaces Vol. 16; no. 15; pp. 18971 - 18979
• Main Authors: He, Wei-Huan, Guo, Yu-Jie, Wang, En-Hui, Ding, Liang, Chang, Xin, Chang, Yu-Xin, Lei, Zhou-Quan, Xin, Sen, Li, Hui, Wang, Bo, Zhang, Qian-Yu, Xu, Li, Yin, Ya-Xia, Guo, Yu-Guo
• Format: Journal Article
• Language: English
• Published: American Chemical Society 17.04.2024
• Subjects: Energy, Environmental, and Catalysis Applications; sodium compensation; electrocatalytic strategy; sodium-ion batteries; electrochemical properties; decomposition voltage
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.4c02268

The formation of a solid electrolyte interphase on carbon anodes causes irreversible loss of Na+ ions, significantly compromising the energy density of Na-ion full cells. Sodium compensation additives can effectively address the irreversible sodium loss but suffer from high decomposition voltage induced by low electrochemical activity. Herein, we propose a universal electrocatalytic sodium compensation strategy by introducing a carbon nanotube (CNT)/MnO2 catalyst to realize full utilization of sodium compensation additives at a much-reduced decomposition voltage. The well-organized CNT/MnO2 composite with high catalytic activity, good electronic conductivity, and abundant reaction sites enables sodium compensation additives to decompose at significantly reduced voltages (from 4.40 to 3.90 V vs Na+/Na for sodium oxalate, 3.88 V for sodium carbonate, and even 3.80 V for sodium citrate). As a result, sodium oxalate as the optimal additive achieves a specific capacity of 394 mAh g–1, almost reaching its theoretical capacity in the first charge, increasing the energy density of the Na-ion full cell from 111 to 158 Wh kg–1 with improved cycle stability and rate capability. This work offers a valuable approach to enhance sodium compensation efficiency, promising high-performance energy storage devices in the future.