Li-S batteries present a low cost, high capacity energy storage alternative, yet critical issues persist which preclude their widespread practical application. These include the dissolution of intermediate species which hampers their performance, decreased capacities with multiple cycling, tailoring a harmonious electrode-electrolyte interface for optimised behaviour and a serious limitation in terms of synthetic approaches to obtaining active electrode materials which are often costly and complex. Here I will present our latest work on demonstrating a facile synthetic strategy to obtain nanostructured Li2S, an active electrode for all-solid-state Li-S batteries, and the application of this electrode in a novel nanoarchitecture that enables high performance over 300 cycles of a three-component free-standing composite comprising Li3PS4/Li2S/C, where the carbon and Li3PS4 serve as conducting media for electrons and Li-ions, respectively. The use of a solid electrolyte avoids intermediate species dissolution and the nanocomposite structure presents an ideal architecture for enhanced electrode electronic and ionic conductivity and excellent compatibility between the solid components, which is reflected in the preservation of the electrode integrity and the build-up of very low interfacial resistances upon cycling. I will discuss how this kind of nanoscale design strategy can improve performance and provide optimised composites as cathodes for all-solid-state batteries. These composites represent some of the best performing materials in the literature for LiS2 currently in terms of capacities and cycling stabilities (~440 mAh g-1 retained at 100 µA/cm2 up to 400 cycles). I will also show our electrochemical data display a well-defined discharge plateau in the voltage profile which has not been previously observed for similar solid-state systems and is reminiscent of that seen for conventional Li-S batteries which employ liquid electrolytes.

Nanostructuring at the interface for efficient and high capacity-performing free standing electrodes in all solid-state Li-S batteries

255th National Meeting (2018)

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