新型锂电池正极材料多硫化碳炔的研究

Carbyne polysulfide as a novel cathode material for lithium batteries

为克服锂/硫电池的正极材料单质硫的导电性差、放电产物的部分溶解导致电池性能下降等问题,设计并制备了一种新型正极材料多硫化碳炔。通过核磁共振、拉曼光谱、X-射线及SEM等手段对其进行了研究,并得到其形态及结构信息,证明材料具有“主链导电、侧链储能”的结构。通过充放电性能测试及循环伏安测试对其电化学性能进行了研究,结果表明该材料具有较高的充放电效率与良好的循环性能,0.4 mA/cm2的放电条件下60次循环后比容量可以达到400 mAh/g,充放电效率接近100%。

The products obtained by co-heating carbon containing carbyne moieties and elemental sulfur, formed by base-induced carbonization of polyvinylidene chloride, have been characterized by 13C-NMR and Raman spectroscopies, XRD and SEM. The material was shown to have a carbon skeleton with attached polysulfide groups, which resembles the theoretical structure of carbyne polysulfide. When used as the cathode in lithium batteries, this material exhibits a high capacity of 600 mAh/g at 0.4 mA/cm^2 and a very stable reversible capacity of 400 mAh/g after 60 cycles. The efficiency of the material is reaches almost 100 % during charge/discharge cycles.