Mesoporous NiCoP microflowers as a superior electrode material for supercapacitors

Abstract In this study, mesoporous NiCoP microflowers are fabricated by a simple direct low-temperature phosphorization of the hydrothermal-prepared Ni0.5Co0.5(OH)2 microflower precursors. The resultant NiCoP material possesses a unique three-dimensional flower-like architecture with high specifc surface area (56.6 m2 g−1) and large pore volume (0.432 cm3 g−1). Utilized as the supercapacitor electrodes, mesoporous NiCoP microflowers outperform the monometallic phosphides (CoxP and Ni2P microflowers) with excellent charge-discharge rate properties (e.g., specific capacity of 1153 and 715 F g−1 at 1 and 30 A g−1, respectively) and superior cycling performance. The specific capacitance of 883 F g−1 can remain stable at 20 A g−1 after 7000 cycles. More importantly, as-prepared NiCoP microflower electrode is able to deliver high energy densities of 48.4 Wh kg−1 and 30 Wh kg−1 at the power densities of 275 W kg−1 and 8.2 kW kg−1, respectively. The enhanced pseudocapacitive performance is mainly attributed to the mesoporous microflower structure and the synergistic combination of different metal elements (Ni and Co) for electrochemical reactions.