Systematic Investigation of Electrochemical Performances for Lithium-Ion Batteries with Si/Graphite Anodes: Effect of Electrolytes Based on Fluoroethylene Carbonate and Linear Carbonates
Enyou Zhao, Yixuan Gu, Shaohua Fang, Li Yang, Shin‐ichi Hirano
Abstract
Fluoroethylene carbonate (FEC) is known as an effective additive to improve the performance of silicon-based anodes, but the improvement is rather limited in full-cell configuration. In this work, we utilize FEC as a main solvent to establish binary or ternary electrolytes and systematically investigate their electrochemical performance in LiNi0.5Co0.2Mn0.3O2∥Si/graphite full-cells. Compared with a commercial electrolyte, the cycle stability and reversibility of the full-cells are remarkably improved during the prolonged cycle test (500 cycles) at ambient temperature. The cells with FEC-based electrolytes demonstrate higher specific capacities at 55 °C for the 200 cycles galvanostatic cycle test, and it shows good rate capacity retention under high current (up to 5 C) at ambient temperature. In particular, the low-temperature performances of the full-cells are prominent; among the tested samples, the FEC/DMC (5:5) electrolyte delivers an outstanding capacity as high as 92.3 mA h g–1 at −40 °C. These results would endow such FEC-based electrolytes with great potential for practical applications.