Integrated Design of a Functional Composite Electrolyte and Cathode for All-Solid-State Li Metal Batteries

• Published in: Batteries (Basel) 2023-06, Vol.9 (6), p.320
• Main Authors: Zhang, Zhenghang, Fan, Rongzheng, Huang, Saifang, Zhao, Jie, Zhang, Yudong, Dai, Weiji, Zhao, Cuijiao, Song, Xin, Cao, Peng
• Format: Article
• Language: English
• Subjects: all-solid-state lithium batteries; Cathodes; Composition; Conductivity; cycle stability; Design and construction; double-layer integrated design; Electrochemical analysis; Electrolytes; Electrolytic cells; Energy storage; garnet oxide (LLZNTO); inorganic-polymer hybrid electrolyte; Interface stability; Lithium; Lithium batteries; Lithium cells; Materials; Molten salt electrolytes; Polymers; Solid electrolytes; Solid state; Solvents
• ISSN: 2313-0105; 2313-0105
• DOI: 10.3390/batteries9060320

Solid composite electrolytes exhibit tremendous potential for practical all-solid-state lithium metal batteries (ASSLMBs), whereas the interfacial contact between cathode and electrolyte remains a long-standing problem. Herein, we demonstrate an integrated design of a double-layer functional composite electrolyte and cathode (ID-FCC), which effectively improves interfacial contact and increases cycle stability. One composite electrolyte layer, PVDFLiFSI@LLZNTO (PL1@L), comes into contact with the LLZNTO (Li6.5La3Zr1.5Nb0.4Ta0.1O12)-containing cathode, while the other layer, PEOLiTFSI@LLZNTO (PL2@L) with a Li anode, is introduced in each. Such a design establishes a continuous network for the transport of Li+ on the interface, and includes the advantages of both PEO and PVDF for improving stability with the electrodes. The Li symmetric cells Li/PL2@L-PL1@L-PL2@L/Li steadily cycled for more than 3800 h under the current density of 0.05 mA cm−2 at 60 °C. Outstandingly, the all-solid-state batteries of LiFePO4-ID-FCC/Li showed an initial specific capacity of 161.5 mA h g−1 at 60 °C, demonstrating a remaining capacity ratio of 56.1% after 1000 cycles at 0.1 C and 74.5% after 400 cycles at 0.5 C, respectively. This work provides an effective strategy for solid-state electrolyte and interface design towards ASSLMBs with high electrochemical performance.