12.6 μm-Thick Asymmetric Composite Electrolyte with Superior Interfacial Stability for Solid-State Lithium-Metal Batteries

• Published in: Nano-micro letters 2024-12, Vol.16 (1), p.181-13, Article 181
• Main Authors: Zhang, Zheng, Gou, Jingren, Cui, Kaixuan, Zhang, Xin, Yao, Yujian, Wang, Suqing, Wang, Haihui
• Format: Article
• Language: English
• Subjects: Anodes; Asymmetric structures; Battery cycles; Cathodes; Composite solid-state electrolyte; Electric fields; Electrolytes; Electrolytic cells; Engineering; High voltages; Interface stability; Lithium; Lithium batteries; Lithium metal battery; Mechanical properties; Metal-organic frameworks; Molten salt electrolytes; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Polyethylenes; Pouch cells; Separators; Solid electrolytes; Solid state; Solid-state lithium metal batteries; Tape casting; Ultrathin asymmetric structure
• ISSN: 2311-6706; 2150-5551; 2150-5551
• DOI: 10.1007/s40820-024-01389-2

Highlights Ultra-thin asymmetric composite solid-state electrolytes with ultralight areal density were designed for solid-state lithium metal batteries, achieving interfacial stability to Li metal and high-voltage cathode. The improved mechanical properties of the electrolyte contribute to the inhibition of Li dendrite growth was demonstrated by both experimental and theoretical simulations. The assembled pouch cell exhibited a high gravimetric/volume energy density of 344.0 Wh kg −1 /773.1 Wh L −1 . Solid-state lithium metal batteries (SSLMBs) show great promise in terms of high-energy–density and high-safety performance. However, there is an urgent need to address the compatibility of electrolytes with high-voltage cathodes/Li anodes, and to minimize the electrolyte thickness to achieve high-energy–density of SSLMBs. Herein, we develop an ultrathin (12.6 µm) asymmetric composite solid-state electrolyte with ultralight areal density (1.69 mg cm −2 ) for SSLMBs. The electrolyte combining a garnet (LLZO) layer and a metal organic framework (MOF) layer, which are fabricated on both sides of the polyethylene (PE) separator separately by tape casting. The PE separator endows the electrolyte with flexibility and excellent mechanical properties. The LLZO layer on the cathode side ensures high chemical stability at high voltage. The MOF layer on the anode side achieves a stable electric field and uniform Li flux, thus promoting uniform Li + deposition. Thanks to the well-designed structure, the Li symmetric battery exhibits an ultralong cycle life (5000 h), and high-voltage SSLMBs achieve stable cycle performance. The assembled pouch cells provided a gravimetric/volume energy density of 344.0 Wh kg −1 /773.1 Wh L −1 . This simple operation allows for large-scale preparation, and the design concept of ultrathin asymmetric structure also reveals the future development direction of SSLMBs.