Yao Zhongran, Zhu Kongjun, Li Xia, Zhang Jie, Li Jun, Wang Jing, Yan Kang, Liu Jinsong
State Key Laboratory of Mechanics and Control of Mechanical Structures, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
ACS Appl Mater Interfaces. 2021 Mar 17;13(10):11958-11967. doi: 10.1021/acsami.0c22532. Epub 2021 Mar 3.
The need for safe storage systems with a high energy density has increased the interest in high-voltage solid-state Li-metal batteries (LMBs). Solid-state electrolytes, as a key material for LMBs, must be stable against both high-voltage cathodes and Li anodes. However, the weak interfacial contact between the electrolytes and electrodes poses challenges in the practical applications of LMBs. In this study, a double-layered solid composite electrolyte (DLSCE) was synthesized by introducing an antioxidative poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP)-10 wt % LiAlTi(PO) (LATP) to the cathode interface, whereas a lithium-friendly poly(oxyethylene) (PEO)-5 wt % LATP was made to come into contact with Li metal. Owing to the heterogeneous double-layered structure of the DLSCE, a high ionic transfer number (0.43), high ionic conductivity (1.49 × 10 S/cm), and a wide redox window (4.82 V) were obtained at ambient temperature. Moreover, the DLSCE showed excellent Li-metal stability, thereby enabling the Li-Li symmetric cells to stably run for over 600 h at 0.2 mA/cm with effective lithium dendrite inhibition. When paired with a high-voltage LiNiCoMnO cathode, the Li/DLSCE/NCM111 cell exhibited excellent electrochemical performance: long-term cyclability with 85% capacity retention could be conducted at 0.2C after 100 cycles corresponding to 100% Coulombic efficiencies.
对具有高能量密度的安全存储系统的需求增加了人们对高压固态锂金属电池（LMBs）的兴趣。固态电解质作为LMBs的关键材料，必须对高压阴极和锂阳极都具有稳定性。然而，电解质与电极之间较弱的界面接触给LMBs的实际应用带来了挑战。在本研究中，通过在阴极界面引入抗氧化的聚（偏二氟乙烯-六氟丙烯）（PVDF-HFP）-10 wt%锂铝钛磷酸盐（LATP）合成了双层固体复合电解质（DLSCE），而使对锂友好的聚（氧化乙烯）（PEO）-5 wt% LATP与锂金属接触。由于DLSCE的异质双层结构，在室温下获得了高离子迁移数（0.43）、高离子电导率（1.49×10 S/cm）和宽氧化还原窗口（4.82 V）。此外，DLSCE表现出优异的锂金属稳定性，从而使锂-锂对称电池能够在0.2 mA/cm下稳定运行超过600小时，有效抑制锂枝晶。当与高压LiNiCoMnO阴极配对时，Li/DLSCE/NCM111电池表现出优异的电化学性能：在0.2C下100次循环后，容量保持率为85%，对应100%的库仑效率，具有长期循环稳定性。
