電化學穩定型鋰硫電池之電極設計

Cathode Design for Electrochemically Stable Lithium–sulfur Batteries

高能量密度之鋰硫電化學儲能電池於近期之研發成果，展現出優於商用鋰離子電池二到三倍之能量密度，以及高安全性與低材料成本等優勢。因此，鋰硫電池已成為後鋰離子儲能技術之研發重點，且列為第三代儲能電池之候選。然而，目前絕大多數鋰硫電池之材料開發、電化學研究，與電池性能展現，多沿用傳統鋰離子電池電極之結構與製程，致使鋰硫電池之獨特固液相轉化電化學無法有效地被運用，並進一步造成鋰硫電池研究多面臨活性物質不足，以及電池電容量利用率、循環性，與能量密度過低之問題。為了解決以上問題，本新知介紹將演示鋰硫電池中電池零組件之設計開發對於電池電化學之顯著影響，並進一步探討電池零組件改質對於電池特性之關係。將討論以本研究團隊設計之多硫化物捕陷層，以抑制液相多硫化物的自由散失；並透過多硫化物捕陷層之高導電性，提升硫電極的電化學反應力與保持被捕陷之多硫化物反應活性。同時，以多硫化物集流體吸收液相之鋰硫電池硫電極活性物質，可具體提升電化學鋰硫電池之電容量及循環週期。

The current progresses in the development of the lithium-sulfur energy-storage technology have demonstrated the possibility in increasing the energy density by two to three times better than those of commercial lithium-ion batteries, as well as high safety and low costs. Although the lithium-sulfur battery is a focus research of the post-lithium-ion energy-storage technologies, most of the current material development, electrochemical research, and battery performance in the lithium-sulfur research still borrow from the conventional lithium-ion batteries. As a result, the current lithium-sulfur batteries cannot effectively exhibit their outstanding conversion electrochemistry and high energy density. In order to address this issue, this prospective report will demonstrate the significant enhancement brought about by the design of lithium-sulfur battery components, and further discuss the relationship between the battery-component modification and the electrochemical characteristics. Specifically, a polysulfide-trapping layer and a polysulfide-hosting current collector developed by our group exhibit the capability in blocking the free polysulfide migration and the fast active-material loss in the lithium-sulfur batteries, respectively, resulting in the improved electrochemical utilization and efficiency.