A LiF-Rich Solid Electrolyte Interphase in a Routine Carbonate Electrolyte by Tuning the Interfacial Chemistry Behavior of LiPF<sub>6</sub> for Stable Li Metal Anodes.

Zhang, Jing; Yue, Xinyang; Wu, Zeyu; Chen, Yuanmao; Bai, Yu; Sun, Kening; Wang, Zhenhua; Liang, Zheng · Nano Lett · 2023

basic_science · Level V

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Abstract

Lithium (Li) dendrite growth in a routine carbonate electrolyte (RCE) is the main culprit hindering the practical application of Li metal anodes. Herein, we realize the regulation of the LiPF<sub>6</sub> decomposition pathway in RCE containing 1.0 M LiPF<sub>6</sub> by introducing a "self-polymerizing" additive, ethyl isothiocyanate (EITC), resulting in a robust LiF-rich solid electrolyte interphase (SEI). The effect of 1 vol % EITC on the electrode/electrolyte interfacial chemistry slows the formation of the byproduct Li<sub><i>x</i></sub>POF<sub><i>y</i></sub>. Such a LiF-rich SEI with EITC polymer winding exhibits a high Young's modulus and a uniform Li-ion flux, which suppresses dendrite growth and interface fluctuation. The EITC-based Li metal cell using a Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> cathode delivers a capacity retention of 81.4% over 1000 cycles at 10 C, outperforming its counterpart. The cycling stability of 1 Ah pouch cells was further evaluated under EITC. We believe that this work provides a new method for tuning the interfacial chemistry of Li metal through electrolyte additives.