Polydopamine‐derived carbon layer anchoring NiCo‐P nanowire arrays for high‐performance binder‐free supercapacitor and electrocatalytic hydrogen evolution

Abstract

Abstract Transition metal phosphides (TMPs) have been extensively and deeply researched as electrode materials for energy‐related applications. However, the inferior stability is still a bottleneck restricting their substantive development. Herein, a freestanding three‐dimensional hierarchical nanostructure (marked as CC@NC/NiCo‐P) is delicately designed for high‐performance supercapacitors and electrocatalytic hydrogen evolution, where the nitrogen‐doped carbon (NC) layer derived from polydopamine serves as an interface coupling bridge for anchoring electroactive nickel cobalt phosphide (NiCo‐P) nanowire arrays on flexible carbon cloth (CC) substrate. Thanks to the robust interaction between the conductive carbon support and NiCo‐P nanowires, the resultant CC@NC/NiCo‐P electrode delivers an ultrahigh capacitance (2175.5 F/g at 1 A/g) and a distinguished rate capability with a capacity retention of 85.8%. The assembled asymmetric supercapacitor can achieve a superior energy density of 28.47 Wh/kg and an ultralong lifespan of 10 000 cycles. In addition, the CC@NC/NiCo‐P electrode shows favorable electrocatalytic activity toward the hydrogen evolution reaction. These results indicate that the strong binding between the NC layer and metal species in TMPs notably improves the stability and electrochemical activity of CC@NC/NiCo‐P. It is expected that this effective strategy to design innovative electrode materials may be promising for the applications in energy‐related fields.

Keywords

• hydrogen evolution reaction
• nanowires
• rate capability
• supercapacitors
• transition metal phosphide