本研究第一部分使用三聚氯氰為核心元素與聚醚胺以各種比例反應，再與 (3-異氰基丙基)三乙氧基矽烷進行化學交聯，最後添加不同濃度的鋰鹽，形成梳狀分枝型複合式有機-無機固態高分子電解質。此系列固態電解質在 30 oC 時，氧鋰比為 32，具有最佳的離子導電度 1.1 × 10-4 S cm-1；電化學穩定性可承受 5.0 V 的氧化裂解電壓；透過 FTIR 與 ssNMR 測量確認固態高分子電解質結構；觀察靜態 7Li MAS NMR鋰譜線寬研究鋰離子的運動性；應用於電致變色元件上，具光學密度差值 0.56、高著色效率 675 cm2 C-1 及良好的循環壽命。本研究所發明的複合式有機-無機固態高分子電解質在鋰電池與電致變色元件應用上，都具有相當的潛力與前途性。 本研究第二部分為自身終止高分歧寡聚物 (STOBA) 塗覆於正極材料 Li(Ni0.4Co0.2Mn0.4)O2 上，透過氮氣吸脫附儀、X-光光電子能譜、電阻測量、掃描式電子顯微鏡、固態 7Li MAS NMR 與 13C CPMAS NMR等方法，研究不同溫度與電荷條件下 STOBA 層的物理與結構變化，以理解 STOBA 層在鋰電池安全機制中的作用。電池在熱失控溫度下 STOBA 層的型態變化從多孔隙到無孔隙；高溫時，電阻的變化顯示 STOBA 層有助於防止內部短路與熱失控；在不同溫度 100 % 荷電狀態下，運用超高轉速 (50 kHz) 的 7Li MAS NMR 光譜觀察鋰離子在 STOBA 層與正極表面微妙的局部環境變化，藉由這些結果理解 STOBA 層在鋰電池安全機制中的作用。 ;The first part of this study is related to the synthesis of organic-inorganic hybrid electrolytes. Cyanuric chloride is employed as the core element to react with polyetheramine in various ratios, and then chemical crosslinking with (3-isocyanatopropyl)triethoxysilane and finally addition of different concentration of lithium salt to form a new organic-inorganic hybrid electrolyte with a core branched structure. The solid hybrid electrolyte possesses a maximum ionic conductivity value of 1.1 × 10−4 S cm−1 at 30 oC and electrochemical stability window of around 5.0 V for the sample with the [O]/[Li] ratio of 32. The structure of the hybrid is confirmed by FTIR and solid-state NMR measurements. The lithium-ion mobility in the hybrid electrolyte is investigated by monitoring the lithium linewidths from static 7Li solid-state NMR. An optical density change value of 0.56 and an exceptionally high coloration efficiency value of 675 cm2 C−1 with good cycle life are obtained when the present hybrid electrolyte is employed to fabricate the prototype electrochromic device. These electrochromic performances are the best as compared to the previously reported electrochromic devices made of hybrid electrolytes. The present organic-inorganic hybrid electrolyte holds great potentials to be used in different electrochemical devices. In the second part of this study, self-terminated oligomers with hyper-branched architecture (STOBA) are developed and coated and melted on a Li(Ni0.4Co0.2Mn0.4)O2 cathode to form a dense polymer film at high temperatures. The physical and structural changes of the polymer layer at different temperatures and state of charge conditions are investigated by nitrogen adsorption-desorption, XPS, resistance measurements, SEM, solid-state 7Li MAS and 13C CPMAS NMR spectroscopy in order to improve the understanding of role of STOBA layer in enhancement of the safety mechanism of lithium-ion batteries. The morphological change of the STOBA layer from the porous to nonporous state at the temperature of thermal runaway of a battery is demonstrated. The change in the resistance values at high temperatures reveals that the STOBA coating is helpful for prevention of internal short-circuit and thermal runaway. Most importantly, the 7Li MAS NMR results acquired at a very high spinning speed (50 kHz) allow the monitoring of the subtle changes in the local environments of the Li+ ions and their interaction and mobility in the STOBA-cathode interface as functions of temperature and charge states. The combined characterization results improve the understanding of role of the STOBA layer in the enhancement of safety features of lithium-ion batteries.
