Temperature effect on electrochemical performances of Li-ion hybrid capacitors

Li-ion hybrid capacitor (LIC) is a type of energy storage device that bridge the gap between Li-ion battery and electrical double-layer capacitor. In the present work, LICs are assembled with activated carbon-based cathode and pre-lithiated hard carbon anode. The effect of temperature on the electrochemical properties of LIC is investigated by galvanostatic charge-discharge tests and electrochemical impedance analyses. The performances of LIC cells with different anode pre-lithiation degree and different cathode composition are comparatively studied. As the temperature decreases, the cell capacity decreases accordingly. The ambient temperature varies from -40 to +60 A degrees C, and the working voltage window is 1.5-4.0 V. At the temperature of -20 and -40 A degrees C, LIC cell can remain 77.7 and 33.8 % of the initial capacity at +25 A degrees C, respectively. Some approaches to improving the low-temperature electrochemical performances of LIC have been proposed.