A novel all solid-state asymmetric supercapacitor with superior electrochemical performance in a wide temperature range by using hydroquinone modified graphene xerogel as cathode and N-doped Ti3C2Tx as anode
To further improve the energy density of supercapacitors, novel asymmetric supercapacitors by using electrode materials with a large different potential window should be designed. In this report, hydroquinone modified graphene xerogel as cathode and N-doped Ti3C2Tx as anode are first applied in all-solid-state asymmetric supercapacitors with a wide voltage window. The hydroquinone modified binder-free graphene xerogels are chosen as the cathode material because of their high potential, high pseudo capacitance, and high conductivity, whereas the N-doped Ti3C2Tx are selected as the anode materials due to their low potential, high specific capacitance, and high conductivity. The as-fabricated asymmetric device shows a potential window of 1.7 V in H2SO4 gel electrolyte, and an excellent adaptability in a wide temperature range from room temperatures to – 20 °C. It is found that an excellent energy density of 33.9 Wh kg–1 for the asymmetric supercapacitor is achieved at – 20 °C. Furthermore, the operation of the asymmetric supercapacitor in a wide temperature range greatly increases the practical application potential of supercapacitors.