Ultrathin Mesoporous NiCo2O4 Nanosheets Supported on Ni Foam as Advanced Electrodes for Supercapacitors

Abstract

AbstractA facile two‐step method is developed for large‐scale growth of ultrathin mesoporous nickel cobaltite (NiCo2O4) nanosheets on conductive nickel foam with robust adhesion as a high‐performance electrode for electrochemical capacitors. The synthesis involves the co‐electrodeposition of a bimetallic (Ni, Co) hydroxide precursor on a Ni foam support and subsequent thermal transformation to spinel mesoporous NiCo2O4. The as‐prepared ultrathin NiCo2O4 nanosheets with the thickness of a few nanometers possess many interparticle mesopores with a size range from 2 to 5 nm. The nickel foam supported ultrathin mesoporous NiCo2O4 nanosheets promise fast electron and ion transport, large electroactive surface area, and excellent structural stability. As a result, superior pseudocapacitive performance is achieved with an ultrahigh specific capacitance of 1450 F g−1, even at a very high current density of 20 A g−1, and excellent cycling performance at high rates, suggesting its promising application as an efficient electrode for electrochemical capacitors.