Electrolyte Chemistry Towards Improved Cycling Stability in Na‐Based Dual‐Ion Batteries with High‐Power/Energy Storage

• Published in: Batteries & supercaps 2021-10, Vol.4 (10), p.1647-1653
• Main Authors: Hou, Xian‐Kun, Li, Shao‐Fang, Li, Wen‐Hao, Liang, Hao‐Jie, Gu, Zhen‐Yi, Luo, Xiao‐Xi, Wu, Xing‐Long
• Format: Article
• Language: English
• Subjects: cathode protection; cycling stability; diving phenomenon; dual-ion batteries; energy density
• ISSN: 2566-6223; 2566-6223
• DOI: 10.1002/batt.202100124

Dual‐ion batteries (DIBs) have attracted great research interests owing to the co‐utilization of cation and anion as charge carriers. Unlike the low energy density (Eden) of supercapacitors and halogen‐ion batteries also with anion working, graphite‐cathode‐based DIBs exhibit obviously higher Eden with high working voltage. However, general electrolytes cannot satisfy the high‐energy demand for Na‐based DIBs with high power density. Herein, we design an effective electrolyte with optimized performance to limit the occurrence of side reactions during cycling, improving the cycling stability and Eden of Na‐based DIBs. Such electrolyte‐modified Na‐DIBs exhibit higher discharge plateau and specific capacity compared to the pristine batteries, contribute preeminent Eden of 370.4 Wh/kg at a high‐power density of 8888.4 W/kg (2.0 A/g), and deliver higher capacity retention of 72 % after 1000 cycles under 40 °C (1.0 A/g). All of these improvements are attributed to the interphase protection of anode/cathode by modified electrolyte, and the increase of diffusion ability under high potential. This strategy not only provides reference significance for enhancing the performance of DIBs, but also promotes the development of DIBs with high‐power/energy and long‐term cycle working condition. It's all about the electrolyte: In this work, a new modified electrolyte is used for Na‐based dual‐ion battery (Na‐DIB). This modified Na‐DIB shows outstanding electrochemical performance, especially high power/energy density and long‐cycling stability. This modification technique paves the way for the design of Na‐DIB electrolytes and promotes the application of Na‐DIB.