Lithium bis(oxalato)borate as an electrolyte for micromesoporous carbide-derived carbon based supercapacitors

1 M solution of lithium bis(oxalato)borate (LiBOB) in ethylene carbonate (EC) and dimethyl carbonate (DMC) mixture (1:1 volume ratio) was studied as an electrolyte for supercapacitors with high surface area micromesoporous carbide-derived carbon electrodes, synthesized from Mo2C. Electrochemical characteristics were studied using cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and constant current charge/discharge methods. The established region of ideal polarizability for a two-electrode system was ∼3.0 V and the limiting capacitance, calculated from EIS data, was 125 F g−1. Three-electrode measurements showed that solid electrolyte interface formation is a very complex process and partially blocks the adsorption and intercalation/deintercalation processes on the negatively charged electrode. The capacitance of a supercapacitor cell decreased by 33% during 5000 galvanic cycles between applied cell voltages from 1.5 V to 3.0 V. Calculated maximal energy and power densities were 42.5 W h kg−1 and 67.3 kW kg−1, respectively. Thus, the tested LiBOB electrolyte is a potential candidate for long-lasting supercapacitors with high power density.