Metal-organic frameworks derived copper doped cobalt phosphide nanosheet arrays with boosted electrochemical performance for hybrid supercapacitors

Developing highly efficient and durable battery-type materials plays key dominant function for achieving high-performance hybrid supercapacitors (HSCs). As a class of promising candidates, transition metal phosphides are largely suffering from the much lower specific capacity as compared their theoretical values as well as fast faded rate capability and durability. Herein, we report the rational design and synthesis of mesoporous Cu doped CoP (Cu:CoP) nanosheet arrays on carbon cloth, which are derived from the oxidation and phosphorization of metal-organic frameworks (MOFs) templates. We find that the introduction of Cu species in CoP matrix can greatly influence the electrochemical performance of the overall electrode. The optimized Cu:CoP electrode delivers a high specific capacity of 113.3 mAh/g at a current density of 8 A/g with much enhanced rate capability and cycling stability. The HSC device assembled by the optimized Cu:CoP and activated carbon can achieve a maximum energy density up to 31.5 Wh/kg, a maximum power density of 15.9 kW/kg as well as excellent long-term cycling stability with 90% retention after 5000 cycles. The present work demonstrates the great potentials of Cu:CoP nanosheet arrays for practical applications and provides a new avenue for the development of novel battery-type electrodes toward high-performance energy-storage systems.