Stable-cycle and high-capacity conductive sulfur-containing cathode materials for rechargeable lithium batteries

Cycle characteristics of conductive sulfur-containing materials (CSMs) synthesized by heating the mixture of polyacrylonitrile and elemental sulfur at a wider temperature region from 250 to 800 °C are presented. The cyclability is improved remarkably for CSMs obtained above 400 °C. A stable capacity of CSM prepared at 450 °C maintains about 470 mAh g−1 and the capacity retention remains ca. 90% after near 380 cycles. Fourier-transform infrared spectroscopy (FTIR) and Raman characterizations disclose that the fundamental chemical structure of CSMs is composed of dehydropyridine type matrix with SS bond in side-chain. Such unique structure and better electrical conductivity ensure the excellent cycle performance of the prepared CSMs.