Template-directed growth of ordered metal-organic frameworks array and derived nickel-cobalt double hydroxide electrode for hybrid supercapacitor and aqueous NiCo-Zn battery

Abstract

Rational design of self-supporting and well-aligned MOF-derived electrode materials is a great challenge. In this work, we report a novel strategy for preparing nickel-cobalt double hydroxide (NiCo-DH) array on nickel foam with template-directed growth of MOF array as the precursor. The obtained sample can be directly applied to both Ni-Zn aqueous secondary battery and hybrid supercapacitor. Due to the many advantages inherited from the MOFs material, the NiCo-DH array displays an ultrahigh reversible specific capacitance (325.6 mAh g−1 at 2 mA cm−2) and excellent rate performance (75.5% of initial capacity retention under 40 mA cm−2). As a cathode for NiCo-Zn batteries, the NiCo-DH electrode exhibits a high specific capacity of 329 mAh g−1 and satisfactory cycling stability. Moreover, the assembled NiCo-DH //active carbon asymmetric supercapacitor exhibited a remarkable capacity of 0.359 mAh cm−1 at 0.5 mA cm−1 and exhibited excellent durability (capacitance retention of 91% after 5 000 cycles). Furthermore, the hybrid device exhibited an impressive energy density of 50.5 Wh kg−1 at a power density of 750 W kg−1. The presented strategy for controlled design and synthesis of MOF-derived self-supported electrode offers prospects in developing highly electrochemical active electrode materials in energy storage devices.