(Invited) Plasma-Thermal Assisted Design of Smart Hybrid Carbon/Metal Sulfide Electrodes

Abstract

The spontaneous increase for advanced energy materials to meet consumer requirements demands the designing of smart, high-performing materials for fabricating next-generation energy devices. The requirement is not only for smart materials but also for manufacturing alternative devices to the rapidly exhausting lithium-based batteries. Currently, sodium-based metal-ion batteries (SIBs) emerged as an alternative to lithium batteries, which also require novel designs of electrodes for achieving high performance. Bridging the gap between theory and realization in SIB development is a significant challenge. A combination of carbon and metal sulfides has been widely reported as a promising electrode structure for SIBs. However, the performance, durability and processing time of such structures have to be improved for practical applications. Considering the importance of electrode designing for battery systems, plasma and thermal processing techniques have been employed to create advanced smart hybrid materials for high-performing SIBs. Plasma produces vertical carbon nanofibers (VCN) directly on a conductive substrate and anchors them with molybdenum. Later, thermal processing was employed to convert them to corresponding metal sulfides. Such designed binder-free composite anode consisting of vertical carbon nanofiber/molybdenum sulfide (VCN/MoS2) nanostructures. The vertically aligned morphology of the binder-free VCN/MoS2 hybrid composites facilitates electrolyte penetration and shortens ion diffusion channels. The direct contact between the VCN to the current collector improves ion/electron conductivity for the electrode. These advantageous features enable the binder-free VCN/MoS2 hybrid composite electrodes to exhibit superior electrochemical properties when used as an anode for SIBs, including exceptional rate capability with a specific discharge capacity of 403 mA h g–1 at a high current density of 3200 mA g–1. These findings could open up the efficient designing of smart hybrid electrodes using green techniques for next-generation energy storage systems.