複合型固態電解質同時具備有機高分子的高機械性能和無機陶瓷粉末的高熱穩定性，因此是應用於鋰金屬電池的理想選擇。然而，複合型固態電解質存在一個嚴重問題，由於有機/無機界面不相容，無機粉末難以均勻分散在有機高分子中，導致團聚現象，從而阻礙鋰離子的傳輸，降低鋰金屬電池的電性能。 在這種情況下，矽烷基偶合劑的加入是一個很好的解決方案。通過矽烷基的親水端與無機粉末(LLZAO)上的-OH鍵結合，以及親油端含氮元素官能基的孤對電子與高分子進行路易斯酸鹼反應，可以改善有機/無機界面。 本實驗選擇了三種含氮官能基的矽烷基偶合劑，分別是3-異氰酸丙基三乙氧基矽烷(IPTS)、3-氨丙基三乙氧基矽烷(KH550)以及3-(2-咪唑啉-1-基)丙基三乙氧基矽烷(ITES)進行比較。 經過3-異氰酸丙基三乙氧基矽烷(IPTS)偶合劑修飾後的複合型固態電解質具有穩定的鋰離子傳輸通道，並展現出較高的離子導電率（在室溫下為8.4 x 10-4 S/cm）。此外，由於無機粉末與有機高分子的界面得到改善，固態電解質本身的拉伸強度達到0.79 MPa。經由組裝NCM811|CSEs|Li固態電池的測試，該電池在室溫充放電速率1.5C下，放電比容量高達125.85 mAh/g，且在0.5C充放電150圈的長循環測試中，比容量保持率高達98.72%。 這種經矽烷偶合劑修飾的複合型固態電解質將會為新一代的全固態鋰金屬電池拓展一條全新的道路。 ;Composite solid electrolytes (CSEs) possess the high mechanical properties of organic polymers and the high thermal stability of inorganic ceramic powders, making them an ideal choice for use in lithium metal batterie s. However, CSEs face a significant challenge: the incompatibility of organic/inorganic interfaces results in inorganic powders not dispersing uniformly within the organic polymer, leading to agglomeration.This agglomeration obstructs the transport of lithium ions and decreases the electrochemical performance of lithium metal batteries. In this context, the addition of silane coupling agents presents a promising solution. By forming bonds between the hydrophilic end of the silane and the -OH groups on the inorganic powder (LLZAO), and through Lewis acid-base reactions between the lone pairs of electrons on the nitrogen-containing functional groups of the hydrophobic end and the polymer, the organic/inorganic interface can be improved. This study selected three nitrogen-containing silane coupling agents for comparison: 3-Isocyanatopropyltriethoxysilane (IPTS), 3-Aminopropyltriethoxy -silane (KH550), and 3-(2-Imidazolin-1-yl)propyltriethoxysilane ( ITES). The composite solid electrolyte modified with 3-Isocyanatopropyltriethoxysilane (IPTS) exhibited stable lithium-ion transport channels and a high ionic conductivity of 8.4 x 10-4 S/cm at room temperature. Furthermore, due to the improved interface between the inorganic powder and the organic polymer, the solid electrolyte itself demonstrated a tensile strength of 0.79 MPa, which is better than the tensile strength of the unmodified powder, 0.46 MPa. Testing the NCM811|CSEs|Li solid-state battery configuration revealed a high discharge specific capacity of 125.85 mAh/g at a 1.5C charge-discharge rate at room temperature, with a capacity retention rate of 98.72% after 150 cycles at 0.5C. This novel design of CSEs with silane coupling agent modification paves the way for a new generation of all-solid-state lithium metal batteries.
