Metal (M = Co, Ni) phosphate based materials for high-performance supercapacitors

With the ever increasing demand for clean, sustainable energy, electrochemical supercapacitors with the advantages of high power density, high efficiency and long life expectancy have become one of the major devices for energy storage and power supply, and have found wide application in hybrid power sources, backup power sources, starting power for fuel cells and burst-power generation in electronic devices. Metal phosphates with the advantages of abundance, environmental friendliness and low cost are emerging as a novel class of promising electrode materials for supercapacitors. This review summarizes recent progress with respect to cobalt and nickel phosphate based micro/nanomaterials applied as supercapacitors, covering ammonium/bimetallic phosphates, cobalt phosphates, nickel phosphates and cobalt/nickel phosphates. Much progress has been made using metal phosphate materials as supercapacitors; however, there is still much room for further improvement.