| For recent ten years, Organic sulfides have attracted enhancing research interests as positive active materials with large energy density, lightweight, low cost and environmentally benign for high power and weightless lithium secondary batteries. But the products during charge-discharge cycling of these materials might dissolve in electrolyte and accordingly cause the collapse of cathode. In this paper, a novel cathode material—carbyne polysulfide was prepared by two methods, one is the dehydrochlorination and sulfuration of PVDC at the same time, and the other is the dehydrochlorination and subsequent sulfuration of PVDC.The products obtained by co-heating carbon containing carbyne moieties and element sulfur have been characterized by 13C-NMR, Raman, XRD and SEM, and it was proved to have carbon skeleton with polysulfide attached on it, which resembles the theoretical structure of carbyne polysulfide. It also showed that in this material, conducting polymer carbyne was used as stable backbones to provide electric conducting channels to offer good electric conductivity, and polysulfide lines as side lines offer high specific capacity. The material prepared by co-heating at 350℃exhibits a high capacity of 600mAh/g at 0.4mA/cm2 and a very stable reversible capacity of 400mAh/g after 60 cycles in the electrolyte of LiPF6. And the efficiency of this material is so high as almost 100% during charge/discharge. The subsequent investigations, include Cyclic voltammograms, Ohm impedance, XRD and Raman test at different discharge stages, showed that new material produced during charge-discharge, but this material is not Li2S, and the identification of it needs more in-depth study.
|
PDF Full Text Request