锂电池阴极材料多硫代聚苯撑的制备及电化学性能

Synthesis and Electrochemical Performance of Anodic Material Poly(p-phenylene) Polysulfide for Lithium Battery

采用阴极材料结构改性的新方法,即以导电的聚苯撑作为骨架,将多硫链以侧链形式连接在主链上.通过苯的聚合、聚苯撑氯代,氯代聚苯撑(PPPCl)的硫代三步合成了多硫代聚苯撑(PPPS),产物结构经13CNMR谱、IR光谱、Raman光谱和元素分析进行了鉴定,其中IR谱中461和615cm-1及Raman谱中470和666cm-1峰分别表明存在S—S键和C—S键,结合其它鉴定结果,证明终产物为多硫代聚苯撑.组装成电池进行充放电性能测试表明,材料在80mA/g的电流密度下放电,比容量为987mA·h/g;在400mA/g下放电,比容量为776mA·h/g.在这两种电流密度下的利用率分别为83.5%和65.7%,具有较高的利用率和较好的大电流性能.在400mA/g的电流密度下放电时,经过25个循环的容量为307mA·h/g.

In order to minimize the electrically nonconductive nature and capacity fade during cycling of sulfur in the anodic material of lithium batteries, a new method for modifying its structure was proposed in this paper. Poly(p-phenylene) polysulfides (PPPS) were synthesized whose skeleton was conducting poly(p-phenylene)(PPP) with polysulfur side lines attaching to it by chlorination of PPP and subsequent sulfuration of poly(p-phenylene) chloride(PPPCl). The resulted products were characterized by ()^(13)C NMR, IR spectrum, Raman spectrum and element analysis. The IR data of 461, 615 cm^(-1) and Raman data of 470 and 666 cm^(-1) suggested the existence of C—S and S—S bonds, which belong to the desired product PPPS. The electrochemical behavior of this material exhibited a high capacity of 987 mA·h/g at 80 mA/g and 776 mA·h/g at 400 mA/g, and its utilization efficiency was 83.5% and 66.7% respectively at the two current densities. The material also showed a stable reversible capacity of 307 mA·h/g after 25 cycles.