Biomass carbon & its prospects in electrochemical energy systems

Activated carbon has now become a vital active material in multifarious applications such as catalytic supports, removal of pollutants, battery electrodes, capacitors, gas storage etc., and these applications require carbon powders with desirable functionalities like surface area, chemical constituents and pore structure. Hence the production of activated carbon materials, especially from cheap and natural bio-precursors (biomass) is a highly attractive research theme in today's science of advanced materials. Though abundant and detailed reports on activated carbons for these applications are available in the literature, creating a consolidated account on the biomass derived activated carbon would serve as a database for the researchers and thus appears justified. Hence an overview on activated carbons (preparation, physical and electrochemical properties) derived especially from biomass for the specific application as electrodes in electrochemical energy devices has been presented to stress the importance of biomass, bioenergy and conversion of wastes into energy concept further. It is certain from the survey of around 100 recent published articles that the biomass carbons have outstanding capability of being applied as electrodes in the energy devices. Particularly, carbon (unactivated) derived from pyrolized peanut shells exhibited a maximum specific capacity of 4765 mAhg−1 in the case of lithium-ion batteries and coconut shell derived carbon in KOH electrolyte gave capacitance of 368 Fg−1 and ZnCl2 activated carbon from waste coffee grounds exhibited 368 Fg−1 in H2SO4. Undoubtedly the study indicates that the biomass derived carbons have economic and commercial promise in the near future.

► The work represent waste-to-energy concept, which is highly essential today. ► The work involves biomass wastes derived carbon that can be applied as electrodes. ► We have wealth of biomass for electrodes in capacitors and lithium-ion cells. ► Biomass wastes derived carbons may replace the costly commercial activated carbons. ► The work would invite research to further add biomass wastes to the existing list.