Plasma and Thermal Processing for Designing Hybrid Carbon-Nickel Sulfide Composite Electrodes

Abstract

There are enormous efforts being made to develop alternative energy storage devices and to meet the energy needs beyond consumer electronics and electric vehicles. Considering batteries and supercapacitors as one of the best performing energy storage devices with high specific energy and power density, there are lots of efforts have been applied to improve the electrochemical features. Amide the different approaches, one of the direct method to improve the performance of such devices are by employing potential electrode materials. Transition metal sulfides are considered as the potential candidates for the next-generation energy storage electrodes. The conversion-reaction induced charge storage mechanism makes them as a promising material for designing high-capacity electrodes for electrochemical energy storage devices. However, poor conductivity and pulverization during the cycling process limits their applications as energy storage devices by limiting the cycle life, capacity and energy density. Thus a combination of metal sulfide phases with hierarchical carbon nanostructures is proposed to address these limitations. Additionally, the direct growth of electrode material on the current collector can overcome the issues related to the binders and internal resistance. In this aspect combining metal sulfides with carbon nanostructures directly grown on current collectors can be used as an advanced electrode material for energy storage applications. Herein, a fast, two-step approach is demonstrated for fabricating a hybrid electrode, consisting of trinickel disulfide (Ni3S2), metallic Ni nanoparticle and vertically aligned multi-walled carbon nanotubes (VCN) in the form Ni3S2/Ni@VCN. The VCN structure is prepared by plasma-assisted techniques, and the nickel sulfide is anchored by the thermal annealing. These Ni3S2/Ni@VCN composites can be directly used as a binder-free electrode for energy storage devices without any further processing, which makes the procedure as a promising technique for the fast fabrication of electrode materials for energy storage devices.