Facile synthesis of dual-morphological MgCo2O4 with remarkable performance for pseudosupercapacitors

Abstract

The facile preparation of electrode materials with superior capacitance can be rationally regarded as a fast and efficient strategy to improve the electrochemical properties of supercapacitors. In this work, dual-morphological MgCo₂O₄ (DMCO) was successfully synthesized on Ni foam (NF) through a simple hydrothermal route. Honeycomb-like and urchin-like MgCo₂O₄ was clearly observed by scanning electron microscopy (SEM) characterization of DMCO, which exhibited an excellent specific surface area of 100.62 m² g⁻¹. The as-prepared DMCO was tested in 2 M KOH electrolyte solution using a standard three-electrode system, and the results showed that DMCO exhibited a superior specific capacitance of 1552.34 F g⁻¹ at the current density of 1 A g⁻¹. After 5500 cycles under the condition of 15 A g⁻¹, 110% of the initial capacitance was retained when it is used as a binder-free electrode material for supercapacitors. Additionally, a DMCO//AC asymmetric supercapacitor (DMCO//AC ASC) was assembled with DMCO as the binder-free positive electrode and active carbon (AC) as the negative electrode, which displayed a high energy density of 27.46 W h kg⁻¹ at a power density of 825.9 W kg⁻¹, and a yellow light-emitting diode could remain lit for 24 min. The cycling performance of DMCO//AC ASC was investigated at the current density of 8 A g⁻¹, where 98.8% of its initial capacitance was retained after 11 000 cycles, which undoubtedly demonstrates its outstanding and prolonged cycle stability. These remarkable electrochemical performances strongly verify that DMCO possesses great potential as a promising material for energy storage.