Hybrid Li-Ion Capacitor Operated within an All-Climate Temperature Range from -60 to +55 °C.

Abstract

Lithium-ion capacitors (LICs) have been considered as an advanced energy storage system owing to their high energy and power densities. However, their application in a wide temperature range is still a great challenge due to the reduced ionic conductivity of the electrolyte and the poor electric conductivity of the battery-type transition metal oxide electrodes. Herein, an all-climate LIC is well-fabricated with TiNb2O7@expanded graphite as the anode and activated carbon as the cathode in an optimized electrolyte, which can be operated within a wide temperature range from -60 to +55 °C. Benefitting from the synergetic effect of the improved electrode and electrolyte, the LIC exhibits an outstanding energy density of 119 W h kg-1 and a power density of 5110 W kg-1 based on the total mass of both negative and positive electrodes. Moreover, it can deliver a capacity retention of as high as 42% at -60 °C and function at a superior rate capability at a high temperature of +55 °C, which exhibits an all-climate feature and the potential for wide applications under some extreme conditions.