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

TLDR

A facile two‑step method was developed to grow ultrathin mesoporous NiCo₂O₄ nanosheets on nickel foam, producing a high‑performance electrode for electrochemical capacitors. The process involves co‑electrodeposition of a Ni–Co hydroxide precursor onto the foam followed by thermal conversion to spinel mesoporous NiCo₂O₄. The resulting nanosheets, only a few nanometers thick with 2–5 nm mesopores, enable rapid electron and ion transport, large electroactive surface area, and excellent structural stability, achieving a specific capacitance of 1450 F g⁻¹ at 20 A g⁻¹ and outstanding cycling performance.

Abstract

Abstract A facile two‐step method is developed for large‐scale growth of ultrathin mesoporous nickel cobaltite (NiCo 2 O 4 ) 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 NiCo 2 O 4 . The as‐prepared ultrathin NiCo 2 O 4 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 NiCo 2 O 4 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.