Novel bouquet-like cobalt phosphate as an ultrahigh-rate and durable battery-type cathode material for hybrid supercapacitors

Abstract

Red phosphorus (RP) is beneficial to industrialization due to its rich resources, chemical stability and environmental friendliness. However, the low electronic conductivity and large volume expansion limit its application for energy storage. Herein, we first used RP to prepare a novel bouquet-like Co3(HPO4)2(OH)2 by the hydrothermal approach as cathode materials for hybrid supercapacitors (HSC), which delivered a large specific capacity (119.2 mA h g−1 at 1 A g−1), a superb rate capability (83.6 mA h g−1 at 100 A g−1) and a splendid electrochemical stability (92% capacity retention after 5000 cycles at 10 A g−1). Furthermore, a novel HSC device assembled with Co3(HPO4)2(OH)2 as the cathode, porous carbon (PC) as the anode showed a high energy density of 44.6 W h kg−1 and a remarkable power density of 33.75 kW kg−1, along with an exceptional cyclic performance (91.8% capacity retention after 10,000 cycles at 3 A g−1). This study not only develops a novel type of high-performance battery-type cathode material, but also provides a new idea for the industrial application of RP.