Achieving stable interphases toward lithium metal batteries by a dilute and anion-rich electrolyte
Dandan Chai, Yazhen Zhu, Chaohong Guan, Tengxun Zhang, Shuai Tang, Hong Zhu, Xiang Li, Yongzhu Fu
Abstract
It is necessary to find an ideal electrolyte suitable for high performance lithium metal batteries (LMBs). Herein, we construct a novel cluster-like and anion-rich dilute electrolyte system by using LiNO 3 and trace lithium trifluoromethanesulfonate (LiOTf) in an ester-based electrolyte. In the designed system, NO 3 – is used as a modulator to regulate the coordination number of solvents and anions, and LiOTf is applied as a solubilizing agent of LiNO 3 and trigger for the generation of large cluster. As a result, an anion-regulated solvation structure (ARSS) is obtained even in a dilute Li-ion concentration (<1.5 M), evidenced by various techniques, enabling the electrolyte a high ion-conductivity which vastly differs from a high concentration electrolyte system. Afterwards, the ARSS facilitates the formation of an inorganic-rich solid electrolyte interface (SEI) on both cathode and anode , ensuring the LMBs high stability and long cycling performance.