Ye Yu, Deng Zhi, Gao Lei, Niu Kangdi, Zhao Ruo, Bian Juncao, Li Shuai, Lin Haibin, Zhu Jinlong, Zhao Yusheng
Academy for Advanced Interdisciplinary Studies & Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China.
Shenzhen Key Laboratory of Solid State Batteries, Southern University of Science and Technology, Shenzhen 518055, China.
ACS Appl Mater Interfaces. 2021 Jun 23;13(24):28108-28117. doi: 10.1021/acsami.1c04514. Epub 2021 Jun 10.
All-solid-state lithium-metal batteries, with their high energy density and high-level safety, are promising next-generation energy storage devices. Their current performance is however compromised by lithium dendrite formation. Although using 3D-structured metal-based electrode materials as hosts to store lithium metal has the potential to suppress the lithium dendrite growth by providing a high surface area with lithiophilic sites, their rigid and ragged interface with solid-state electrolytes is detrimental to the battery performance. Herein, we show that LiOHBr-containing poly(ethylene oxide) (PEO) polymer electrolytes can be used as a flexible solid-state electrolyte to mitigate the interfacial issues of 3D-structured metal-based electrodes and suppress the lithium dendrite formation. The presence of LiOHBr in a PEO matrix can simultaneously improve the mechanical strength and lithium ion conductivity of the polymer electrolyte. It is confirmed that LiOHBr does not only induce the PEO transformation of a crystalline phase to an amorphous phase but also serves as an anti-perovskite superionic conductor providing additional lithium ion transport pathways and hence improves the lithium ion conductivity. The good interfacial contact and high lithium ion conductivity provide sufficient lithium deposition sites and uniform lithium ion flux to regulate the lithium deposition without the formation of lithium dendrites. Consequently, the LiOHBr-containing PEO polymer electrolyte in a lithium-metal battery with a 3D-structured lithium/copper mesh composite anode is able to improve the cycle stability and rate performance. The results of this study provide the experimental proof of the beneficial effects of the LiOHBr-containing PEO polymer electrolyte on the 3D-structured lithium metal anode.
全固态锂金属电池具有高能量密度和高安全性，是很有前景的下一代储能装置。然而，其当前性能受到锂枝晶形成的影响。尽管使用三维结构的金属基电极材料作为主体来存储锂金属，通过提供具有亲锂位点的高表面积有抑制锂枝晶生长的潜力，但它们与固态电解质的刚性且参差不齐的界面不利于电池性能。在此，我们表明含LiOHBr的聚环氧乙烷（PEO）聚合物电解质可作为柔性固态电解质，以缓解三维结构金属基电极的界面问题并抑制锂枝晶形成。PEO基体中LiOHBr的存在可同时提高聚合物电解质的机械强度和锂离子电导率。证实LiOHBr不仅诱导PEO从晶相转变为非晶相，还作为反钙钛矿超离子导体提供额外的锂离子传输途径，从而提高锂离子电导率。良好的界面接触和高锂离子电导率提供了足够的锂沉积位点和均匀的锂离子通量，以调节锂沉积而不形成锂枝晶。因此，在具有三维结构锂/铜网复合阳极的锂金属电池中，含LiOHBr的PEO聚合物电解质能够提高循环稳定性和倍率性能。本研究结果为含LiOHBr的PEO聚合物电解质对三维结构锂金属阳极的有益作用提供了实验证据。
