A.M. Numan-Al-Mobin, B. Maddipudi, V.S. Amar, R.V. Shende, H. Fong
South Dakota School of Mines and Technology,
Keywords: electrospinning, 3D nanofibrous sponge, hydrothermally generated biochar, supercapacitor electrode, energy storage
Summary:The goal of this study is to process a typical waste product, namely the biochar obtained from the oxygen-limited hydrothermal system of biomass (e.g., corn stover), into the value-added product. Particularly, the 3D carbon nanofibrous sponges are prepared by converting the hydrothermally generated biochar where the electrospun polymer (i.e., polyacrylonitrile - PAN and polyimide - PI) nanofibers are working as the skeleton support. In the precursor sponge, the weight ratio of biochar to polymer is varied from 4:1 up to 12:1. Note that the organic carbon content of the biochar is 85%. The heat treatment of the precursor sponge includes the stabilization in air and carbonization in argon. This process transforms it into a carbon nanofibrous sponge. The morphological structures of the sponge before and after carbonization are characterized. It is observed that the carbonization increased the elasticity and the mechanical stability of the sponge. In addition, the electrochemical study of the manufactured carbon nanofibrous sponge indicates its potential use in making supercapacitor electrodes. It appears that the increase in the biochar weight ratio could be effective in increasing the energy density of the supercapacitor.