Shidong Song,Yongqiang Xu,Yanli Ruan,Hong Wang,Dequan Zhang,Joykumar Thokchom,Donghai Mei
Amorphous Li–La–Zr–O (LLZO) solid-state electrolyte thin films are promising alternatives to the well-established lithium phosphorus oxynitride (LiPON) electrolyte for all-solid-state lithium batteries due to their potentially higher Li-ion conductivity and stability. Herein, the enhancement methodology in the ionic conductivity of amorphous LLZO-based thin films is investigated. By doping with Ta, the conductivity of the amorphous LLZO film at 30 °C (3.9 × 10–7 S cm–1) can be enhanced by up to an order of magnitude (2.6 × 10–6 S cm–1), ascribed to tuning Li conduction in local near-order LLZO nanodomains. On that basis, an isomeric Li–La–Zr–Ta–O (LLZTO) amorphous–crystalline composite thin film is prepared via incorporating cubic LLZTO particles into the amorphous LLZTO matrix. The composite film with 10 wt % cubic LLZTO filler can further achieve an ionic conductivity of 0.8 × 10–5 S cm–1 at 30 °C, which is comparable to the best values obtained for the state-of-art LLZO-based thin films. Li transport through the well-connected cubic LLZTO filler network and along the interfaces between the crystallites and the amorphous matrix in the LLZTO composite thin film may offer fast and long-range Li-conduction pathways, which supplement the ionic conduction in the amorphous matrix with short-range-ordered and long-range-disordered structures.
Li Bangxing,Yi Xianlin,Xie Zhenjun,Wu Fei,Kang Xing,Kang Shuai,Hu Xiaolin
Composite solid electrolyte (CSE), especially the composite room temperature solid electrolyte (CRTSE), is emerging as the promising electrolyte for all-solid-state lithium batteries (ASSLB) due to their ability to combine the desirable properties of ceramic and polymer-based electrolytes and the room temperature operation condition. In this paper, the CRTSE with polyethylene oxide (PEO), bis(fluorosulfonyl)imide (LiTFSI), succinonitrile (SN), LLZTO inorganic fillers, and cross-linked ethoxylated trimethylolpropane triacrylate (ETPTA) was proposed. With the help of lithium dendrite suppression via cross-linked microscopic pore structure, enhancement of the ionic conductivity via LLZTO fillers, and wide electrochemical window via SN, the obtained LCSE showed high ionic conductivity (2.12 × 10 −4 S cm −1 ), high Li + transfer number ( t Li + = 0.55), and stable electrochemical window (5.0 V vs Li/Li + ) at room temperature. The Li symmetrical cell with LCSE can cycle over 500 h stably with current density of 0.1 mA cm −2 and 0.5 mA cm −2 at room temperature. The full solid-state LiFePO 4 cell can successfully work over 200 cycles with capacity retention ratio of about 70% at room temperature.
It is a persistent goal for solid-state electrolytes to enhance their ionic conductivity while maintaining good mechanical strength to potentially inhibit lithium dendrites. In this work, we introduce garnet-type Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) fillers and polyacrylonitrile (PAN) into thermoplastic polyurethane (TPU) to fabricate a composite solid-state electrolyte. The TPU matrix contains hard segments (−NH−COO−) that provide efficient mechanical support and soft segments (−O−) responsible for good flexibility and elasticity. When blended with PAN, hydrogen bonds form between the functional groups of PAN and TPU, establishing strong intermolecular connections that further enhance the structural/electrochemical stability of the electrolyte. A stable polymer/filler interface can be constructed through the ion-dipole coordination interaction between the metal ions at the LLZTO surface and the −CN groups of PAN. Benefiting from the intricate interactions among the PAN/TPU dual polymers and the LLZTO filler, the composite electrolyte exhibits not only exceptional flexibility (a tensile strain of 208%) and tensile strength (40 MPa), but also a good ionic conductivity of 2.33 × 10 −4 S cm⁻¹ at room temperature, a high oxidation potential of 4.48 V, and an excellent Li + transference number of 0.79. The Li||LiFePO 4 battery employing this composite solid-state electrolyte exhibits remarkable electrochemical stability, delivering an initial discharge capacity of 127.4 mAh g −1 at 0.3C and room temperature, and maintains a capacity retention of 91.9% after 600 cycles. This work provides a new electrolyte modification strategy for next-generation solid-state lithium metal batteries.
危险品化学品经营许可证（带存储）