Boron carbon nitride (BCN): an emerging two-dimensional nanomaterial for supercapacitors

Boron carbon nitride (BCN) is a new-generation ultrathin two-dimensional (2D) nanomaterial that has received great interest in the recent past. The unique properties of BCN have led to several applications, including catalysis, electrochemical energy storage, and energy generation. Global energy crisis and climate change necessitate sustainable energy storage systems to work together with renewable energy conversion systems. Supercapacitors are high-power electrochemical energy storage systems that find applications in the current and next-generation electric vehicles and smart-grids to supply power on demand. The electrochemical performance parameters, such as specific capacitance, energy density, and cycle life, are mainly dependent on the electrode-active materials used in supercapacitors. Although various electrode-active materials are invariably used as electrodes in supercapacitors, materials with 2D morphology have received great interest. This is due to their unique properties, such as large surface area to volume ratio, good electronic conductivity, availability of enormous surface-functional sites, fast electrolyte ion-diffusion, and good chemical and electrochemical stabilities. Herein, we report the recent developments on supercapacitors based on electrode-active materials prepared from ultrathin layered 2D BCN-based nanostructures. We describe the synthesis methods and the properties of BCN nanostructures, preparation of BCN-based hybrids/heterostructures/nanocomposites, and their electrochemical performance evaluation with possible challenges and a future outlook. This review describes the recent developments on the synthesis methods and properties of boron carbon nitride (BCN). The supercapacitor electrode preparation and testing of BCN and BCN-based hybrids/heterostructures/nanocomposites are also included.