Two-dimensional materials and its heterostructures for energy storage

Abstract The periodic increment in the global energy demand is keeping researchers busy recognizing the potential energy materials for safe, efficient, and inexpensive energy storage. With the imminent exhaustion of fossil fuel and its subsequent environmental consequences, there has been enormous demand for eco-friendly, renewable, cheap, and portable secondary battery that could provide energy storage for variable applications. In past few decades, Li-ion batteries (LIBs) have ruled the market as the leading battery technology and have been the primary source of power in portable electronic devices and electric vehicles owing to their high output voltages, high power density, long cycle life, high rate capability, low maintenance, and wide working temperature ranges. However, with explosion in LIB market and increasing demand for faster charging/discharging electrodes, conventional three-dimensional (3D) electrodes fell short in terms of capacity and charge/discharge kinetics. Burdened by slow charge–discharge process, phase transformations due to reactions, large volume expansions, and mechanical failures, 3D electrodes are being replaced by single-layer-thick two-dimensional (2D) materials that might elude chances of mechanical failure and volume expansions. Favorable characteristics such as flexibility, good conductivity, lightweight, high surface reactivity, along with ability to be altered to form intricate nano-structures, have altogether made 2D materials a promising platform to advance the course for interface tailoring for evolution of battery systems.