Boosting Sodium Compensation Efficiency via a CNT/MnO<sub>2</sub> Catalyst toward High-Performance Na-Ion Batteries
Wei‐Huan He, Yu‐Jie Guo, Yu‐Jie Guo, Enhui Wang, Liang Ding, Xin Chang, Yuxin Chang, Zhou‐Quan Lei, Sen Xin, Hui Li, Bo Wang, Qian-Yu Zhang, Xu Li, Ya‐Xia Yin, Yu‐Guo Guo, Yu‐Guo Guo
Abstract
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)/MnO 2 catalyst to realize full utilization of sodium compensation additives at a much-reduced decomposition voltage. The well-organized CNT/MnO 2 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.