A modified template-removal process to improve the specific surface area and hierarchical porosity of carbon materials

CaCO3-templating is a strategy for synthesizing porous carbon (PC) materials that has been widely used for decades. In this work, a modified template-removal process, soaking the pyrolysis product by hydrochloric acid solution, was proposed to optimize the graphitization degree, morphology, specific area, and pore size distribution of the products. The tests results demonstrated that the PC product obtained by a modified template method (M-TC) exhibited a transformation in microstructure such as an enhanced specific surface area and more plentiful hierarchical pores as compared with those PC materials obtained by conventional strategy. The potential formation mechanisms are proposed as well. When the M-TC sample loaded sulfur was applied as a cathode material for a Li-S battery, it delivered a high initial discharge capacity (1475 mAh g−1) and a stable discharge capacity (874 mAh g−1) after 50 cycles at 0.1 C. The modified template-removal strategy could bring inspirations on synthesis design and extend potential applications of commercial PC materials.