Boosting Pseudocapacitive Energy Storage Performance via both Phosphorus Vacancy Defect and Charge Injection Technique over the CoP Electrode

Abstract It is an indisputable fact that electrochemical performance is always ameliorated by introducing proper phosphorus vacancy defect into electrode materials. In this work, the lattice-like CoP grown on the nickel foam with appropriate concentration of vacancies is fabricated successfully. The specific capacitance of 1865 F g-1 is improved by 1.7 times compared with the pristine CoP of 1125 F g-1 at the current density of 1 A g-1. Meanwhile, the deliberately designed electrode also possesses great stability of retention rate up to 90% after 5000 cycles. Before the electrode is assembled into the asymmetric supercapacitor, the potential window is altered by electrode potential blend technique in order to utilize capacitances of anode and cathode efficiently. Subsequently, the supercapacitor is studied in the electrochemistry systematically. The results show that power density is up to 737 W kg-1 as energy density is 31 W h kg-1. Meanwhile, the capacitance retention rate remains 88% after 5000 cycles. It is a meaningful guide for exploring efficient energy storage equipment that appropriate vacancies are injected into electrode materials, and optimal potential windows are obtained via electrode potential blend technology.