High-rate operation of sulfur/mesoporous activated carbon composite electrode for all-solid-state lithium-sulfur batteries

Abstract

All-solid-state lithium-sulfur batteries are promising from the perspective of high safety, low cost, and high capability. Herein, composites of sulfur and microporous carbon (MSP20, MSC30) are prepared by a melt diffusion process, and their performance as electrode materials are compared with that of composites based on nanocarbons. In addition to the type of carbon, the degree of mixing with solid electrolytes is an important factor in the formation of ionic/electronic conduction pathways. The all-solid-state cell using S-MSC30-Li₃PS₄ shows a high initial discharge capacity of 1488 mAh per gram of sulfur at 25 °C at a current density of 1.3 mA cm⁻² and operates reversibly at a high current density of 12.7 mA cm⁻² (3C) at 100 °C. The amorphization of sulfur is effective for obtaining high capacity and sulfur impregnated into the meso- and micropores of carbon is more active than sulfur that forms nanocomposites with nanocarbon.