Metal Organic Framework Derived Heterogeneous CoNiP@CoNiSe for High Performance Asymmetric Supercapacitor

Transition metal phosphides and selenides hold immense promise for advancing energy storage technologies. However, sluggish reaction kinetics and limited rate performance present major challenges to large-scale energy storage. Herein, a highly tunable metal–organic framework (MOF) template was employed to design CoNiP@CoNiSe through a strategy that integrates both nanostructures and heterostructures. The nanosheet structure enables rapid electron and ion transport while providing abundant electroactive sites, which in turn improves electrical conductivity and specific capacity. Furthermore, the heterostructure between CoNiP and CoNiSe optimizes the electronic structure of the host material, facilitating OH^– adsorption and desorption, accelerating electron transfer and enhancing the efficiency of redox processes. Benefiting from the structural advantages and synergistic effects, the obtained CoNiP@CoNiSe electrode showcases a high specific capacity of 931 C g^–1, an ultrafast rate capacity (652 C g^–1 at 30 A g^–1, 70% retention) and outstanding long-term cycling durability, with a capacity retention of 83% after 10,000 cycles. Beyond that, when configured in an asymmetric supercapacitor setup as CoNiP@CoNiSe//AC, it attains a notable energy density of 47.3 W h kg^–1, coupled with a robust power density of 266.7 W kg^–1. Moreover, the configuration maintains an impressive 78% of its capacitance even after enduring 10,000 cycles. This innovative approach to heterostructure construction offers a valuable blueprint for elevating the electrochemical performance of transition metal-based electrodes in supercapacitor applications.