Biomass-Derived Activated Carbon Substituted Polyoxometalates for Energy Applications

Abstract

The rapid industrial and societal evolution has led to a population boom and a deepening energy crisis, rapidly depleting non-renewable sources. This urgency has shifted focus towards renewable energy sources like solar and wind power, despite their intermittency issues due to their reliance on environmental conditions. To address these challenges, advances in energy storage technologies, including batteries, fuel cells, and supercapacitors, have become critical. These innovations are essential in ensuring a continuous energy supply from renewable sources, marking a significant step towards a sustainable and energy-secure future. All kinds of batteries, such as lead and lithium-ion batteries, are examples of devices that store electric energy and have a high energy density.Nevertheless, most batteries have a low power density, which prevents them from meeting the need for energy that is more powerful and faster. In order to bridge these gaps, a supercapacitor was designed to store and release energy at a rapid pace. Because of its high-rate capabilities, it is ideal for supplying energy to electric cars, tramways, diesel engine starters, wind turbines, computers, lasers, cranes, and so on. Nanostructured carbon materials such as activated carbon, graphene, and carbon nanotubes have long been utilized as electrodes due to their inherent properties. Recently, biomass-derived activated carbon has emerged as a promising option for electrode material due to its impressive mechanical strength, cost-effectiveness, and eco-friendliness. In this work, we have investigated using Polyoxometalates (POMs) based nanocomposites to enhance the performance of a wide range of supercapacitor devices. POMs are inorganic metal oxide cluster assemblies of high-valent transition metal (Mo, V, W) with exceptional redox properties, structural diversity, and stability. These pseudocapacitive POMs act as multi-electron transfer redox agents, effectively serving as an electron sponge. However, using POMs directly as an electrode material is not feasible due to their low conductivity and high solubility in water, which leads to leaching. To overcome this, POMs are often wired over high-conductive surfaces to improve their conductivity. Our nanohybrid approach successfully leverages the synergistic effects between the elements to deliver superior energy storage performance.