MOF-derived hollow NiCoP combined with rGO for high-performance hybrid supercapacitors

The combination of transition metal compounds and carbon materials is considered effective in optimizing electrode material performance. In this work, some simple methods are used to embed bimetallic phosphides into carbon material frameworks to form heterostructures. The process includes the in situ growth of cobalt-based zeolitic imidazole frameworks on rGO, the formation of bimetallic hydroxides by Ni2+ etching, and further high-temperature phosphating to form a NiCoP/rGO hollow nanocomposite. Benefiting from the synergistic effect between NiCoP and rGO, NiCoP/rGO-20 exhibits the best electrochemical properties, has a high specific capacity of 250.9 mAh g−1 at a current density of 1 A g–1, and has good rate performance (62.7% retention at 10 A g–1). Furthermore, a hybrid supercapacitor was assembled with NiCoP/rGO-20 as the positive electrode and activated carbon (AC) as the negative electrode. The NiCoP/rGO-20//AC HSC device has a high energy density of 60.6 Wh kg–1 at a power density of 749 W kg–1 as well as excellent cycling stability with 83.7% capacitance retention after 10,000 cycles at 10 A g–1. This work provides a new strategy for the development of high-performance energy storage composites.