Lithium–sulfur pouch cells with 99% capacity retention for 1000 cycles†

Abstract

The lithium–sulfur (Li–S) battery is a highly promising candidate for next-generation battery systems. However, the shuttle effect of polysulfides or the dendrites and side reactions of lithium metal anodes limit the cycle life of batteries. In particular, at the pouch cell level, achieving long-term cycling stability is extremely challenging. Here, we have constructed a Li–S pouch cell with sulfurized pyrolyzed poly(acrylonitrile) (SPAN) as the cathode and graphite (Gr) as the anode, introducing lithium-ions through a facile in situ pre-lithiation method. In carbonate-based electrolytes, the SPAN cathode can avoid the shuttle effect, while the Gr anode can exclude the interference of lithium metal. By rationally controlling the cycling conditions to suppress the loss of active lithium and the increase in resistance, a SPAN‖Gr pouch cell with 1000 cycles and 99% capacity retention rate can be ultimately obtained. The A h-level pouch cell can stably cycle for 1031 times with 82% capacity retention rate and pass multiple safety tests. This design is expected to fundamentally improve the long-term cycling stability of Li–S pouch cells and it has great potential in the field of large scale energy storage due to its absence of transition metal elements.