Energy and power performance of electrochemical double-layer capacitors based on molybdenum carbide derived carbon

Abstract

Cyclic voltammetry, constant current charge/discharge, and electrochemical impedance spectroscopy have been applied to establish the electrochemical characteristics for electric double-layer capacitor (EDLC) consisting of the 1 M (C 2H 5) 3CH 3NBF 4 electrolyte in acetonitrile and micro/mesoporous carbon electrodes prepared from Mo 2C, noted as C(Mo 2C). The N 2 sorption (total BET specific surface area ( S BET ≤ 1855 m 2 g −1), micropore area ( S micro ≤ 1823 m 2 g −1), total pore volume ( V tot ≤ 1.399 m 3 g −1) and pore size distribution (average NLDFT pore width d NLDFT ≥ 0.89 nm) values obtained have been correlated with the electrochemical characteristics for EDLCs (region of ideal polarizability (Δ V = 3.0 V), characteristic time constant ( τ R = 1.05 s), gravimetric capacitance ( C m ≤ 143 F g −1)) dependent strongly on the C(Mo 2C) synthesis temperature. High gravimetric energy (35 Wh kg −1) and gravimetric power (237 kW kg −1) values, normalised to the total active mass of both C(Mo 2C) electrodes, synthesised at T synt = 800 °C, have been demonstrated at cell voltage 3.0 V and T = 20 °C.