A HIGH ENERGY AND POWER DUAL-ION BATTERY

Abstract

As the alternative of Lithium-ion Batteries, Dual-Ion Batteries (DIBs), utilizing the intercalation mechanisms of anions into graphite cathode and cations into anode materials, have been proposed as a novel energy storage system for the long cycle life, low cost and environmental impact. However, due to the high potential of anions intercalation into graphite, electrolytes with high oxidizing stability are required. Herein, all-fluorinated electrolyte (1 M LiPF6 in fluoroethylene carbonate (FEC)/ bis(2,2,2-trifluoroethyl) carbonate (FDEC)/ hydrofluoroether (HFE) 2:6:2 by volume) enables the DIB to be operated within a wide voltage window with excellent cycling stability. Moreover, Li2TiSiO5 anode material with high reversibility and proper working potential (0.28 V vs. Li+/Li), which supports high-rate operation due to free of lithium dendrite compared with graphitic anode, is applied here. This dual ion cell (graphite // Li2TiSiO5) exhibits high cycling stability with 71% capacity retention after 500 cycles and excellent rate performance (15 C).