Ni–MOF derived NiMoO4@Ni2P core–shell nanosheets on Ni foam via an ion exchange method for a high–performance pseudocapacitor

Reasonably tuning the structure of Ni 2 P based complex electrode is decisive to boost its applications in supercapacitor. Herein, we demonstrate the design and preparation of NiMoO 4 @Ni 2 P nanosheet arrays with unique core–shell architecture on Ni foam (NF) for pseudocapacitor. The directly grown Ni–MOF on NF was used to couple with NiMoO 4 via an ion exchange between BDC 2− and MoO 4 2- , which is crucial to form a stable NiMoO 4 @Ni 2 P/NF core–shell structure during the subsequent phosphatization. The NiMoO 4 @Ni 2 P/NF electrode can deliver a high capacitance of 3655.1 mF cm −2 at 1 mA cm −2 with a remarkable cycling stability (95.35 % over 4000 cycles). Additionally, the assembled NiMoO 4 @Ni 2 P/NF–2//AC/NF device achieves a stable working voltage of 1.7 V and delivers a superior energy density of 0.155 m Wh cm −2 at a power density of 1.705 mW cm −2 . The outstanding performance of pseudocapacitor is mainly ascribed to the stable diffusion channel, rich reactive species and hetero–interface, enabling fast electrochemical reaction kinetics.