Wood biochar – a low-cost, high-performance alternative to advanced nanoporous carbon materials

On June 7, Wood Biochar Monolith-Based Approach to Increasing the Volumetric Energy Density of Supercapacitor, an article by Professors Charles Jia and Don Kirk, was published in ACS Publications – a high-impact interdisciplinary journal reporting on energy research.

Energy storage technologies are central to the economy’s electrification and renewable energy utilization and crucial to tackle the climate change challenge. According to the International Energy Association, the world will need 266 GW of energy storage capacity by 2030 to keep global warming below 2 °C. Electrochemical energy storage (EES) systems can constitute a significant portion of that capacity. While the past couple of decades has seen an unprecedented expansion in energy storage material research, it is increasingly recognized that the volumetric performance of EES systems is more relevant to real-world applications. Supercapacitors are particularly attractive for storing energy from intermittent sources, such as solar farms, windmills, and regenerative braking of electric vehicles, due to their fast charging/discharging capability and long cycling life. However, the low energy density and high manufacturing costs hinder their full acceptance and large-scale applications. Three factors determine the volumetric energy density of a device: volumetric capacitance of the electrode material, operating voltage window, and device packing efficiency.

Wood biochar monoliths (WBMs) have a low-tortuosity porous structure and a conductive carbon matrix, a combination desirable for binder-free electrodes with high energy density. Jia and Kirk’s paper reports a novel approach for fabricating high-performance, WBM-based thick electrodes. Their study outlines a practical method to increase the volumetric energy density, demonstrating the potential of WBMs as a low-cost, high-performance alternative to advanced nanoporous carbon materials such as graphene and carbon nanotubes.