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Date of Award
Chemical Engineering and Materials Science
Simon Ka Yuen Ng
Firstly, effects of CoS loading (10%, 20%, and 30%) on the surface of multi-walled carbon nanotubes (MWCNTs) on electrochemical performance of Li-S batteries were investigated. 20% CoS@MWCNTs exhibit the best performance due to the well-distributed of CoS on the surface of MWCNTs and adsorption of lithium polysulfide by CoS. Furthermore, 20% CoS nanoparticles anchored on the surface of functionalized multi-walled carbon nanotubes (f-MWNTs) were applied as novel sulfur cathode materials to boost the electrochemical performance of Li-S batteries. Secondly, the issue related to lithium metal in Li-S system was addressed by adding the novel organic additives amino thiophenol (ATP) in electrolyte solution. The three isomers of ATPs were utilized to study their different effects on Li-S batteries. The Li-S cells with 4-ATP exhibit the best not only due to the steric stabilization, but also the amine in 4-ATP facilitates the reactivity of thiol group in 4-ATP by deprotonating the thiol to form the more nucleophilic thiolate. At last, the novel solid electrolytes PEO-TMCs/IL-LiTFSI was firstly applied to fabricate all-solid-state Li-S batteries and exhibit good cycling performance and competitive EIS data. This study demonstrates that the transition metal carbides (TMCs) is one of the promising fillers which can not only mix with PEO, but also be compatible with Li metal anode well. It should be a good strategy to combine TMCs with alternative conductive polymers such as PVDF and PAN as solid electrolytes for Li-S or Li-ion batteries.
Wang, Zhao, "Investigation Of Sulfur Cathode Modification And Lithium Metal Protection For Advanced Lithium Sulfur Batteries, As Well As Polymer Solid Electrolyte For Solid-State Lithium Sulfur Batteries" (2022). Wayne State University Dissertations. 3703.