Systematic Investigation of Electrochemical Performances for Lithium-Ion Batteries with Si/Graphite Anodes: Effect of Electrolytes Based on Fluoroethylene Carbonate and Linear Carbonates

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.