Supercapacitor electrode based on few-layer h-BNNSs/rGO composite for wide-temperature-range operation with robust stable cycling performance

Currently, developing supercapacitors with robust cycle stability and suitability for wide-temperature-range operations is still a huge challenge. In the present work, few-layer hexagonal boron nitride nanosheets (h-BNNSs) with a thickness of 2−4 atomic layers were fabricated via vacuum freeze-drying and nitridation. Then, the h-BNNSs/reduced graphene oxide (rGO) composite were further prepared using a hydrothermal method. Due to the combination of two two-dimensional (2D) van der Waals-bonded materials, the as-prepared h-BNNSs/rGO electrode exhibited robustness to wide-temperature-range operations from −10 to 50°C. When the electrodes worked in a neutral aqueous electrolyte (1 M Na₂SO₄), they showed a great stable cycling performance with almost 107% reservation of the initial capacitance at 0°C and 111% at 50°C for 5000 charge−discharge cycles.