In-situ construction of P-doped Ni0.5Cu0.5Co2O4 with 1D/2D hierarchical nanostructure for high-performance hybrid supercapacitors

Multi-component synergy and controlled structural design can effectively tailor the electronic structure and multiply kinetic reactions, substantially enhancing the electrode material's performance. Herein, a novel P-doped Ni0.5Cu0.5Co2O4 with a 1D/2D hierarchical nanostructure is synthesized in situ. The hierarchical architecture significantly improves the exposure of active areas and facilitates the diffusion of electrolyte ions. Theoretical calculations reveal that the P-doping is instrumental in fine-tuning the electronic structure, enhancing conductivity, and increasing the adsorption energy of OH−. These theoretical insights were corroborated by electrochemical measurements. Remarkably, the optimized P-Ni0.5Cu0.5Co2O4 exhibited an ultrahigh capacitance of 2872.1F g−1 at 1 A g−1, which is 1.58 times that of before phosphating (1810.6F g−1). In addition, a hybrid supercapacitor based on 9-P-Ni0.5Cu0.5Co2O4 was assembled, delivering an impressive energy density of 71.6 Wh kg−1 at a power density of 800 W kg−1. Furthermore, the device demonstrated outstanding cyclic performance, maintaining 87.73 % of its initial capacitance even after 10,000 cycles. This study not only showcases the superior performance of P-Ni0.5Cu0.5Co2O4 but also provides a promising strategy for developing high-energy storage material.