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Development of New Cathodic Interlayers with Nano-Architectures for Lithium-Sulfur Batteries 10.17863/CAM.22944 Zhao, Teng 0000000223982495 Kumar, R. Vasant Issues with the dissolution and diffusion of polysulfides in liquid organic electrolytes hinder the advance of lithium–sulfur (Li-S) batteries for next generation energy storage. To trap and re-utilize the polysulfides, brush-like, zinc oxide (ZnO) nanowires based interlayers were prepared ex-situ using a wet chemistry method and were coupled with a sulfur/multi-walled carbon nanotube (S/MWCNT) composite cathode. The cell with this configuration showed a good cycle life at a high current rate ascribed to (a) a strong interaction between the polysulfides and ZnO nanowires grown on conductive substrates; (b) fast electron transfer and (c) an optimized ion diffusion path from a well-organized nanoarchitecture. A praline-like flexible interlayer consisting of titanium oxide (TiO2) nanoparticles and carbon (C) nanofiber was further prepared in-situ using an electrospinning method, which allows the chemical adsorption of polysulfides throughout a robust conductive film. A significant enhancement in cycle stability and rate capability was achieved by incorporating this interlayer with a composite cathode of S/MWCNT. These results herald a new approach to building functional interlayers by integrating metal oxides with conductive frameworks. The derivatives of the TiO2/C interlayer was synthesized by changing the precursor concentration and carbonization temperature. Finally, a dual-interlayer was fabricated by simply coating titanium nitride (TiN) nanoparticles onto an electro-spun carbon nanofiber mat, which was then sandwiched with a sulfur/assembled Ketjen Black (KB) composite cathode with an ultra-high sulfur loading. The conductive polar TiN nanoparticles not only have a strong chemical affinity to polysulfides through a specific sulfur-nitrogen bond but also improve the reaction kinetics of the cell by catalyzing the conversion of the long-chain polysulfides to lithium sulfide. Besides, carbon nanofiber mat ensures mechanical robustness to TiN layer and acts as a physical barrier to block polysulfides diffusion. The incorporation of dual interlayers with sulfur cathodes offers a commercially feasible approach to improving the performance of Li-S batteries. University of Cambridge 2018-05-02 Thesis Doctoral Doctor of Philosophy (PhD) en Krishnan-Ang Studentship https://www.repository.cam.ac.uk/handle/1810/275684 https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/562e7ad6-4013-45d2-a7b1-f049fd832356/download 87eda9de84448d1f82354d60eee3eb5f https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/cedf3b96-2d4d-4891-93d9-14dbe84cce00/download b3dd9dcd87cd6f0fc3123461fa41c2c7 https://www.rioxx.net/licenses/all-rights-reserved/ Lithium-sulfur Batteries Interlayers Nanostructure Polysulfides Chemical interaction Metal oxides Metal nitrides Electrospinning Carbon nanofibers