Boron-oxy-carbide sheets: A wide voltage symmetric supercapacitor electrode with high temperature tolerance

Abstract

In view of exploring the boron-based nanostructures for the application of energy storage, we have synthesized boron-oxy-carbide material with hydrothermal assisted annealing process and analyzed its performance in aqueous and organic electrolyte. The ability of BOC material to operate both in positive and negative region in Li2SO4 electrolyte encourage us to construct a symmetric device. Splendidly, the BOC material breaks the restriction of low thermodynamic potential window of water (1.23 V) equipped with high cell voltage of 2 V and shown excellent energy density of 16.15 Wh kg−1 at 500 W kg−1 of power density. To extend its operating voltage, a symmetric coin cell was fabricated and tested in TEABF4 electrolyte. As expected, the cell operates upto 3 V and shows maximum energy density of 38.75 Wh kg−1 at 1125 W kg−1 with tremendous rate capability. Moreover, the temperature dependent electrochemical behavior was tested at different temperature from −15 °C to 80 °C. The device shows considerable increment in the specific capacitance with 15.8 F g−1 at −15 °C and 26.24 F g−1 at 80 °C.