Fabrication of Cobalt-Doped Lignin Base Carbon Nanotubes Composite Material for Energy Storage Applications

The development of high-performance, sustainable, and economical electrodes with superior capacity and cyclic stability is crucial for the advancement of energy storage devices. Carbon nanotubes (CNTs) has garnered considerable interest as a potential electrode material for energy storage applications, owing to its high capacity, natural abundance, cost-effectiveness, and eco-friendliness. In the present study, lignin was combined with CNTs to synthesize a Co-CNTs/lignin composite electrode material via hydrothermal method, for enhance energy storage performance. The structure and surface morphology of the synthesized Co-CNTs/lignin composite is characterized by X-ray diffraction (XRD), RAMAN spectroscopy, X-ray Photoelectron Spectroscopy (XPS), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET). The thermal stability of the composite sample was also studied by thermogravimetric analysis (TGA). The Co-CNTs/lignin composite exhibit enhanced electrochemical kinetics and electrical conductivity compared to pristine Co-CNTs and Co-lignin. The Co-CNTs/lignin composite material has shown remarkable electrochemical performance, it exhibits high specific capacitance, an energy density, and a power density at a low current density. The composite material showed outstanding electrochemical stability, maintaining 98% of its original capacitance and exhibiting an impressive coulombic efficiency of 81% after 1000 charge-discharge cycles at a current density of 5 A g−1. The obtained data indicated that the composite materials exhibit superior performance in energy storage devices.