Co(OH)2@MnO2 nanosheet arrays as hybrid binder-free electrodes for high-performance lithium-ion batteries and supercapacitors

Abstract

Co(OH)₂@MnO₂ nanosheet arrays were directly grown on nickel foam via two-step electrodeposition method with subsequent heat treatment at 170 °C. The hybrid electrode, where the electrodeposited Co(OH)₂ and MnO₂ nanosheets were inlayed with each other, was formed and employed as a binder-free anode material for a lithium-ion battery (LIB) and as an electrode for a supercapacitor (SC). For both applications, LIB and SC, the Co(OH)₂@MnO₂ nanosheet electrode exhibited appreciable cycling stability with high specific capacity as well as specific capacitance and rate capability. The excellent electrochemical performances of this hybrid nanosheet electrode were probably ascribed to their unique 3D architecture, which provides large active sites for efficient electrochemical reactions and the synergistic effects of the two active materials. The electrodeposition method appears to be suitable for the fabrication of binder-free, nanostructured, hybrid arrays, and as demonstrated here, the Co(OH)₂@MnO₂ nanosheet could potentially be used as a high-performance LIB and SC electrode material.