盐酸活化对石墨相氮化碳(g-C3N4)结构和g-C3N4/S锂硫电池正极复合材料性能的影响
Effect of hydrochloric acid activation on properties of graphite carbonitride(g-C3N4) structure and g-C3N4/S cathode composites for lithium-sulfur batteries

以三聚氰胺为原料制备石墨相氮化碳（g-C3N4），加入盐酸进行水热处理得到酸活化的g-C3N4。研究了盐酸活化对g-C3N4结构、形貌及锂硫电池g-C3N4/S正极复合材料电化学性能的影响。实验结果表明：盐酸活化处理后，g-C3N4的层间距变化不显著。随着盐酸浓度增大，g-C3N4比表面积先增大后减小，当盐酸浓度为2.5wt%时，比表面积最大为86.1 m2·g-1，与未处理g-C3N4的13 m2·g-1相比提高了5~6倍；盐酸活化g-C3N4/S正极复合材料的比容量和循环性能也呈现先增大后减小的趋势，当盐酸浓度为2.5wt%时，比容量和循环性能最好，比容量为1 538 mAh·g-1，循环50次后容量保持率为77.8%，电化学性能与比表面积呈强相关性。 Graphite carbonitride (g-C3N4) was prepared from melamine and hydrothermally treated with hydrochloric acid to obtain acid-activated g-C3N4. The effects of hydrochloric acid activation on the structure and morphology of g-C3N4 and the electrochemical performance of g-C3N4/S cathode composites were investigated experimentally. The experimental results show that g-C3N4 layer spacing does not change significantly after hydrochloric acid activation. With the increase of hydrochloric acid concentration, the specific surface area of the g-C3N4 sample first increases and then decreases. When the concentration of hydrochloric acid is 2.5wt%, the maximum specific surface area is 86.1 m2·g-1, which is 5-6 times higher than untreated g-C3N4 of 13 m2·g-1. The specific capacity and cycle performance of hydrochloric acid activated g-C3N4/S cathode composites also increase first and then decrease. When the concentration of hydrochloric acid is 2.5wt%, the specific capacity and cycle performance of the hydrochloric acid activated g-C3N4/S cathode composite sample are the best, and the specific capacity is 1 538 mAh·g-1. After 50 cycles, its capacity holding rate is 77.8%. The electrochemical performance and specific surface area of hydrochloric acid activated g-C3N4/S cathode composites show a strong correlation