Charge/discharge characteristics of sulfurized polyacrylonitrile composite with different sulfur content in carbonate based electrolyte for lithium batteries

The charge/discharge characteristics of sulfurized polyacrylonitrile composite (SPAN) cathodes with different sulfur content in conventional carbonate based electrolyte for rechargeable lithium batteries have been investigated. The good performance of SPAN in the carbonate based electrolyte indicates a material difference between SPAN and elemental sulfur/carbon composite materials. The SPAN with sulfur contents of 33.7%, 42.0% and 46.3% are prepared by control of heating time. The SPAN with sulfur content of 42.0% shows the best electrochemical performance, it can deliver stable cycling capacity over 700 mAh g−1, and keep capacity retention over 97% after 80 cycles in the electrolyte of 1 M LiPF6/EC + DEC. The average capacity degradation rate is less than 0.03% per cycle excluding the first discharge capacity. Prototype 100 mAh Li/SPAN cell is assembled, showing energy density of 437 Wh kg−1 excluding the weight of package and capacity retention of 90.4% after 30 cycles at 100% depth of discharge. This study demonstrates that the sulfurized polyacrylonitrile composite in the electrolyte of 1 M LiPF6/EC + DEC is a promising battery chemistry, which materials are abundant, of low cost and easily available, to fabricate Li/SPAN batteries, paving an alternative avenue to develop high performance lithium batteries for energy storage and vehicular application.

► The sulfurized polyacrylonitrile composite shows good performance. ► Stable cycling capacity over 700 mAh g−1 of the composite. ► Close to 100% utilization of elemental sulfur. ► Capacity retention over 97% after 80 cycles. ► Average capacity degradation rate less than 0.03% per cycle.