The high-capacity lithium/sulfur (Li/S) battery, with low cost and improved safety, is one of the most promising technologies for next generation energy storage systems. However, its practical application has been plagued by poor cycling stability and high self-discharge caused by formation of soluble polysulfide intermediates.

Researchers at PNNL have designed a flexible interwoven sulfurized polyaniline (SPANI hereafter) to imbed sulfur in the form of an S/SPANI composite. The soluble long chain polysulphides produced during repeated cycling are effectively constrained within the SPANI spatial network through physical and chemical interactions. Even after 500 cycles a capacity retention rate of 68 percent is observed in the S/SPANI composite with a reversible capacity of about 600 mAh g-1. Compared with a conventional carbon matrix, the framework of the elastic SPANI polymer functions very differently in that the volume of SPANI varies proportionately with that of S to better accommodate cycling. The amine groups and/or imine groups decorated on SPANI surface further interact or attract the soluble polysulfides anions leading to superior electrochemical performance. This new approach for designing sulfur-based electrode materials also may be useful in other battery applications.