Abstract:
In terms of sustainable development and environmental issues, the design and fabrication of efficient energy storage devices will be more critical in the future than at any time in the past. L-S batteries are promising candidates for such a purpose due to their high specific capacity and low environmental impact.
In our previous work, the summary of typical strategies in S cathode engineering and the corresponding characteristics and properties are illustrated. Clearly, morphology and porosity control are essential for constructing matrices with high S loadings, fast ion and electron transfer, confinement of PS and buffering of volume variation.
Fig Timeline for the advances in Li-S batteries and typical strategies in S cathode.
In our research work of constructing matrices with confinement of PS, we designed novel S@PTh composites with Core-shell structures via an in situ chemical oxidative polymerization method. The conductive PTh shell acts as a conducting additive and a porous adsorbing agent, enhancing the capacity and cycle life of the S cells to a large degree. In order to improve the utilization and rate capability, we further developed the novel concept of dual core-shell composites and investigated the effects of different conductive polymer coatings on the electrochemical performance of MWCNT@S composites. In Graphene based 2D/3D composites, we incorporated 1D core-shell MWCNT@S composites into the interlayer galleries of graphene (GS) through a facile solutionassembly process. The unique 3D sandwich-type architecture of the GS-MWCNT@S composite brought advantages in electron/ ion transfer, the confinement of PS and the accommodation of volume variation. We proposed a systematic modification of cathode and separator with polydopamine to synergistically mitigate the shuttle effect and improve the performance of lithium sulfur batteries. This systematic modification yields excellent capacity retention, high capacity, and high Coulombic efficiency.
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