Harnessing organic electrolyte for non-corrosive and wide-temperature Na-Cl2 battery
Qiuchen Xu, Shanshan Tang, Nachuan Li, Yan Wang, Xiaoju Zhao, Xiao Zhang, Shitao Geng, Bin Yuan, Shuo Wang, Zhaofeng Ouyang, Meng Liao, Linlin Ma, Ming Shang, Yifan Sun, Huisheng Peng, Hao Sun
Abstract
Rechargeable sodium-chlorine (Na-Cl2) batteries show great promise in grid energy storage applications due to their high electrochemical performance. However, the use of highly corrosive thionyl chloride (SOCl2)-based electrolytes has severely hindered their real-world applications. Here we show a non-corrosive ester (methyl dichloroacetate) as a promising alternative to SOCl2, which can form a non-corrosive electrolyte with aluminum chloride and sodium bis(fluorosulfonyl)imide for high-performance rechargeable Na-Cl2 batteries. The resultant battery shows a reversible capacity of up to 1200 mAh g−1 at a current density of 100 mA g−1 calculated based on the mass of carbon with a discharge voltage of ~2.5 V, a wide temperature range from −40 to 80 °C, and long-term cycling stability of 700 cycles at −40 °C, which outperforms conventional rechargeable Na-Cl2 batteries and state-of-the-art Na metal batteries. The electrochemical performance and safety have been further extended to fibre batteries, which realize wearable applications of rechargeable Na-Cl2 batteries. Based on donor number and charge transfer as two key descriptors, we further propose the design principle of organic electrolytes for rechargeable Na-Cl2 batteries, which can fully unlock the designability and sustainability of organic solvents towards practical Na-Cl2 batteries. Rechargeable sodium-chlorine (Na-Cl2) batteries hold promise for grid energy storage but face challenges of corrosive thionyl chloride (SOCl2) electrolytes. Here, authors introduce a non-corrosive ester as an alternative, enabling Na-Cl2 batteries with a wide temperature range from −40 to 80 °C.