Synthesis and Characterization of Hydromagnesite-templated and Lignin-derived Porous Carbon for Supercapacitor Electrode Application

Abstract

The growing environmental concerns associated with climate change highlight the need for sustainable energy storage devices. Efforts are now being made to employ biomass as a precursor for carbon-based supercapacitors. In line with this, this study investigated the use of Kraft ligninderived porous carbon with flower-like morphology as an active material in electrodes in symmetric electrochemical double layer capacitors (EDLCs). The flower-like porous carbon was prepared by self-assembly of lignin onto hydromagnesite and then activated using phosphoric acid. The activated carbon exhibited a Brunauer-Emmett-Teller (BET) surface area of 240 m2·g-1 and a pore volume of 0.46 cm3·g-1. The assembled supercapacitor device based on the activated carbon showed a capacity of 1 mC and a specific capacitance of 27 mF·g-1 at a current density of 0.05 A·g-1. Consequently, the highest energy density achieved was 0.36 mW·h·kg-1 at 2 W·kg-1. The performance of the supercapacitor was largely attributed to the small surface area and poor porous structure of the activated carbon. As such, further improvements in the active material are needed to achieve its optimum performance in supercapacitors.