- 學位論文
矽酸鋰人工固態電解質介面於金屬鋰充電電池之研究
Lithium Silicates as An Artificial Solid Electrolyte Interface for Rechargeable Lithium Metal Batteries
摘要
鋰金屬負極擁有高達3860 mAh g-1的理論電容量，此一電容量遠遠高於現行的所有商用負極材料，這也是科學家們之所以極力想發展金屬鋰充電電池的原因。然而，鋰金屬負極在電池的循環過程中容易形成針狀的枝晶結構，這將導致電池的短路而有安全上的疑慮。除此之外，固態電解質介面也是一問題所在，恐影響效率與循環壽命，並產生非活性鋰成為枝晶結構的隱憂。 本篇研究中，我們成功合成出不同的矽酸鋰相，並利用簡單的乾式塗佈法，在鋰金屬上塗佈一人工固態電解質介面，保護鋰金屬不直接與電解液接觸，減緩上述電池循環時可能的安全壽命等問題。後續結果證實，矽酸鋰保護層不僅可減少不必要的介面反應、促進鋰離子的傳導性，亦可有效延長電池整體壽命，相信對於日後發展長循環壽命的金屬鋰充電電池必能有所貢獻。
並列摘要
The major motivation of replacing lithium-ion batteries with lithium metal batteries is to obtain higher energy density by adopting the metallic lithium anode (3860 mAh g-1, theoretically), which means they can store more energy in the same volume or weight. One of the main challenges of rechargeable lithium metal batteries is the formation of lithium dendrites during the charging process. Lithium dendrites are tiny needle-like structures that can grow from the surface of the lithium metal electrode and penetrate the separator, causing battery short-circuiting. This can lead to safety issues, including the potential for fire or explosion. Another challenge is the formation of solid-electrolyte interface (SEI) on the surface of the lithium metal electrode, which can reduce the battery's efficiency and cycle life. The SEI layer can also lead to the formation of inactive lithium and increase the risk of dendrite growth. In the present work, various lithium silicates have been synthesized to be implemented as the artificial SEI layer via a facile dry coating method. The lithium silicate coating acts as a protective barrier that prevents direct contact between the lithium metal and the electrolyte, which may cause undesirable side reactions and reduce the efficiency and lifespan of the battery. The lithium silicate-based artificial SEI layer improves the stability and efficiency of lithium metal batteries by reducing unwanted surface reactions, improving ion transport kinetics, and protecting the lithium metal anode from mechanical deformation and unstable SEI formation during extended cycling. This laminated lithium anode structure could be an effective design for the future development of long-cycle-life lithium metal batteries.