Activated carbon from pyrolysis of peanut shells as cathode for lithium-sulfur batteries

Abstract

The utilization of low-value, abundant and sustainable biomass materials for high-value energy storage application is remarkable important nowadays. Among the most promising next generation energy storage batteries, we can find lithium-sulfur batteries that have a high theoretical specific capacity and high energy density. In the present article we propose the use of peanut shells, a regional industrial waste of high availability and polluting level, as a source of carbonaceous material for the preparation of sulfur cathode of this kind of batteries. Different carbon were obtained from pyrolysis of peanut shells by changing the conditions of the synthesis, which was performed through acid or basic pre-treatment of the biomass. The effects of these treatments in the physical characteristics of the carbonaceous materials and their performance as cathodes in lithium-sulfur batteries were studied. Chemical treatments of shells before pyrolysis as well as the post-pyrolysis treatment of the produced carbon have influence on the porosity of the final materials and therefore on their electrochemical performance. The best electrode carbon was obtained from acid-treated peanut shells (and washed after pyrolysis) obtaining an initial specific capacity of 778 mAh/g with high cycling stability and a coulombic efficiency higher than 95%. We also compare the performance of the best peanut shells-derived biocarbon with one commercial carbon (Super P). In this work, we study a simple route to develop low-cost carbon materials arising from residual biomass which may extend their use in energy storage applications.