Metal Organic Framework‐Derived Anionic P‐Substitution toward CoNiSe‐P with Excellent Electrochemical Stability for Supercapacitor

Abstract The regulation of nanostructures and composition can significantly enhance the electrochemical activity and accelerate electrochemical reaction kinetics of electrode material. Herein, metal organic framework(MOF) is used as self‐sacrificing templates to prepare CoNiSe‐P by hydrothermal with following selenylation and phosphorization treatment. Due to the hollow porous structure, rich electrochemical active sites and elements synergistic influence, the obtained CoNiSe‐P electrode shows a high capacity of 838 C g ⁻¹ , which is much higher than CoNiSe (322 C g ⁻¹ ) and CoNiP (616 C g ⁻¹ ). Furthermore, CoNiSe‐P electrode shows excellent rate characteristic (685 C g ⁻¹ at 20 A g ⁻¹ ) and ultrahigh electrochemical stability with capacity retention of 99.6% after 10 000 cycles. More importantly, an asymmetric supercapacitor is assembled with CoNiSe‐P as the positive electrode and nitrogen‐doped porous carbon as the negative electrode delivers an energy density of 42.4 Wh kg ⁻¹ at 266.6 W kg ⁻¹ and maintains a specific capacitance of 96.8% after 10 000 cycles. Significantly, the asymmetric supercapacitor shows a high energy density up to 21.3 Wh kg ⁻¹ at a very high power density of 21.3 kW kg ⁻¹ , higher than those of previously reported asymmetric supercapacitors.