The Ethylene Carbonate-Based Electrolyte of Lithium-Ion Capacitors

Soft-packaged lithium ion capacitors (LICs) with activated carbon and soft carbon were assembled using two kinds of ethylene carbonate-based organic electrolytes. Their electrochemical performance, including DC internal resistance, C-rate, impedance spectra and cycleability, was studied. The results showed that the LICs with the lithium bis(fluorosulfonyl)imide salt (1.2 mol/L LiFSI : (EC/PC/DEC), which was obtained by adding propylene carbonate (PC) to the mixed solvent of ethylene carbonate (EC) and diethylene carbonate (DEC), possess lower internal resistance, better rate capability and higher low temperature performance. This can be significant for developing electrolytes for low internal resistance and low-temperature LICs.