Journal Article

Sulfolane-Based Flame-Retardant Electrolyte for High-Voltage Sodium-Ion Batteries

Ye, Shenghua, Peng, Jie, Liu, Pei, Li, Meng, Zhang, Qianling, Huang, Tao, Yang, Xuming, Ren, Xiangzhong, Xiao, Biwei, He, Xuanlong, Deng, Jiaojiao, Huang, Zhencheng, Chen, Weibin, Liu, Jianhong, Lin, Qingyun, Ouyang, Xiaoping, Hu, Jiangtao, Liu, Yuying

2025

Overview

Highlights NaTFSI/SUL:OTE:FEC facilitates the formation of S, N-rich, dense and robust cathode–electrolyte interphase on NaNMF cathode, which improves the cycling stability under high voltage. By utilizing NaTFSI/SUL:OTE:FEC, the Na||NaNMF batteries achieved an impressive retention of 81.15% after 400 cycles at 2 C with the cutoff voltage of 4.2 V. The study offers a reference for the utilization of sulfolane-based electrolytes in sodium-ion batteries (SIBs), while the nonflammability of the NaTFSI/SUL:OTE:FEC enhances the safety of SIBs. Sodium-ion batteries hold great promise as next-generation energy storage systems. However, the high instability of the electrode/electrolyte interphase during cycling has seriously hindered the development of SIBs. In particular, an unstable cathode–electrolyte interphase (CEI) leads to successive electrolyte side reactions, transition metal leaching and rapid capacity decay, which tends to be exacerbated under high-voltage conditions. Therefore, constructing dense and stable CEIs are crucial for high-performance SIBs. This work reports localized high-concentration electrolyte by incorporating a highly oxidation-resistant sulfolane solvent with non-solvent diluent 1H, 1H, 5H-octafluoropentyl-1, 1, 2, 2-tetrafluoroethyl ether, which exhibited excellent oxidative stability and was able to form thin, dense and homogeneous CEI. The excellent CEI enabled the O3-type layered oxide cathode NaNi 1/3 Mn 1/3 Fe 1/3 O 2 (NaNMF) to achieve stable cycling, with a capacity retention of 79.48% after 300 cycles at 1 C and 81.15% after 400 cycles at 2 C with a high charging voltage of 4.2 V. In addition, its nonflammable nature enhances the safety of SIBs. This work provides a viable pathway for the application of sulfolane-based electrolytes on SIBs and the design of next-generation high-voltage electrolytes.

• Publisher: Springer Nature Singapore,Springer Nature B.V,SpringerOpen
• Subject: Batteries / Cathodes / Cycles / Electrolytes / Energy / Engineering / Flame retardant / Flame retardants / High voltage / High voltages / Layered oxide cathode / Leaching / Nanoscale Science and Technology / Nanotechnology / Nanotechnology and Microengineering / Oxidation resistance / Sodium / Sodium-ion batteries / Solvents / Stability / Sulfolane-based electrolyte / Transition metals