复合工艺对硫碳复合材料性能的影响

Effects of composite technology on the performance of S / C composite

以活性炭为碳材料,用熔融法、溶剂法、溶剂热浸渍法和沉淀法制备硫碳复合材料,通过SEM、XRD、循环伏安和充放电测试,研究复合工艺对硫碳复合材料性能的影响。溶剂法和溶剂热浸渍法制备的复合材料硫含量不可控,对溶剂选择性较强,且溶剂热浸渍法的操作繁琐,高温反应可能生成有毒物质,复合材料易团聚;熔融法制备的复合材料硫分布均匀,硫-碳间分子结合力强,具有良好的电化学性能;沉淀法操作复杂,硫含量不易控,但硫颗粒可达微纳米级,分布均匀,与碳结合力强,适合于制备石墨烯等前驱体复合物,制备的硫碳复合材料以0.2 C在1.5-3.0 V充放电,首次放电比容量达702.5 m Ah/g,循环20次的容量保持率为72%。

S/C composite for lithium-sulfur battery was synthesized by melting method, solvent method, solvent heat dipping method and precipitation method with activated carbon as carbon materials. The effects of composite technology on the performance of S/C composite were studied by SEM ,XRD ,cyclic vohammetry and charge-discharge tests. The sulfur contents of composites prepared by solvent method and solvent heat dipping method were uncontrollable, had strong selectivity for solvent. The operation of solvent heat dipping method was complicated, high-temperature reactions might generate toxic substances, the composites reunion easily. Sulfur could distributed uniformly and combined with carbon molecular strongly in the composite prepared by melting method, fine electro- chemical performance was shown. The operation of precipitation method was complex,the sulfur content was not easy to control,but it could generate micro-nano sulfur particles which could distribute uniformly, combined with carbon strongly. The method was suit- able for the preparation of graphene composite precursor. When charged-discharged at 0. 2 C in 1.5 - 3 V, its initial specific discharge capacity was 702. 5 mAh/g,the capacity retention ratio was 72% after 20 cycles.