Activator-induced tuning of micromorphology and electrochemical properties in biomass carbonaceous materials derived from mushroom for lithium-sulfur batteries

The micromorphology characteristics of carbon host materials play an important role in stabilizing the structure and restricting the polysulphides in lithium-sulfur batteries. In our work, four kinds of biomass carbon materials derived from mushroom have been synthesized by a facile activation method using H3PO4, K2CO3, KOH and ZnCl2 as activators and the correlation between micromorphology characteristics and electrochemical properties in these biomass carbon materials have been systematically investigated. The electrochemical performance of lithium sulfur batteries is highly dependent on pore size, pore volume and surface area of activated carbon matrixes. The H3PO4-, K2CO3-, KOH- and ZnCl2- activated carbon materials exhibit the fluffy, dense, anomalous and molten morphologies, respectively, which induce the initial discharge capacities of 1357, 943, 1013 and 860 mAh g−1 in their S/C composites; and their capacity retentions at 0.1C are 54%, 37%, 38% and 35% after experiencing 100 cycles, respectively. These may be attributed to the combination effects of surface area and pore size/volume in their carbon matrixes. Our study show that activator can effectively tailor pore size, pore volume and surface area of biomass carbon host materials and thus improve electrochemical performance of S/C composites for lithium sulfur batteries.

93