Anion‐Decoordination Cell Formation Process Stabilizes Dual Electrodes for Long‐Life Quasi‐Solid‐State Lithium Metal Battery

Abstract

Compared with the complete replacement of liquid electrolytes by solid electrolytes, the hybrid quasi‐solid electrolyte (HQSE) has more practical application potential due to its high thermal stability and high ionic conductivity as well as good interface wettability. In this work, a HQSE film is prepared using the Li6.40La3Zr1.40Ta0.60O12 (LLZTO) nanoparticles localized composite liquid electrolyte (CLE) composed of TEGDME (0.5 m LiTFSI) organic electrolyte and Pyr14TFSI ionic liquid. The HQSE film exhibits high ionic conductivity of 1.77 × 10−3 S cm–1 and a high Li‐ion transference number of 0.56 at 25 °C. More importantly, a formation process is designed by utilizing the oxidative decomposition of the free TFSI– anions caused by the substitution of ion cluster Li(TFSI)n+1n− by Li(TEGDME)x+ in HQSE, achieving the in‐situ construction of the stable and complete cathode electrolyte interface and solid electrolyte interface in the cathode and anode simultaneously, and benefiting from the liquid electrolyte being confined to the surface of LLZTO particles, the HQSE film finally exhibits high stability to the dual electrodes, ensuring that the quasi‐solid‐state Li metal battery exhibits capacity retention of 80% after 1000 cycles at 0.2 C rate, and 90% after 500 cycles at 0.5 C rate.

Regulating the reduction reaction pathways via manipulating the solvation shell and donor number of the solvent in Li-CO 2 chemistry

“…Since the formation of the SEI is determined by the coordination environment of Li + ions, which can lead to different interfacial decomposition behavior ( 23 , 24 ), Raman spectroscopy and density functional theory (DFT) calculations were jointly employed to reveal the solvation structure and electrolyte configuration of the DMSO and TEGDME-based electrolytes. SI Appendix , Figs.…”

Tape-Casting Method of Hybrid Solid Electrolytes with a Residual Active Solvent of Tetraethylene Glycol Dimethyl Ether

“…Therefore, HSE in this work exhibits superior electrochemical properties. Compared with the HQSE in our previous works, 34 blending with PEO can improve the flexibility and film forming of hybrid electrolytes so that the thickness of the HSE film can decrease to 70 μm and the film can be bent and stretched, which is suitable for the preparation of flexible batteries. In addition to being used as a solvent to dissolve and disperse components in the casting method, TEGDME can also be used as an active component of the hybrid electrolyte.…”

“…Moreover, the Li 1s spectrum verifies the Li salt components in SEI are LiF (56.0 eV), Li 2 CO 3 (55.3 eV), and Li 2 O (54.0 eV). − Based on the above results, the SEI layer whose main components are LiF, Li 2 CO 3 , and Li 2 O formed on the surface of Li metal anodes. Compared with the HQSE in our previous works, blending with PEO can improve the flexibility and film forming of hybrid electrolytes so that the thickness of the HSE film can decrease to 70 μm and the film can be bent and stretched, which is suitable for the preparation of flexible batteries. In addition to being used as a solvent to dissolve and disperse components in the casting method, TEGDME can also be used as an active component of the hybrid electrolyte.…”

“…Another function of TEGDME is an active component reserved in the HSE. In our previous work, we prepared a hybrid quasi-solid electrolyte containing a composite liquid electrolyte Pyr 14 TFSI–TEGDME (1:1, v/v), which exhibits superior stability with both anodes and cathodes . To reserve TEGDME with a volume ratio of 1:1 to Pyr 14 TFSI–2.0 M LiTFSI as a composite liquid component in the HSE, the drying time was controlled by monitoring the residual mass of the TEGDME solvent.…”

“…In our previous work, we prepared a hybrid quasi-solid electrolyte containing a composite liquid electrolyte Pyr 14 TFSI−TEGDME (1:1, v/v), which exhibits superior stability with both anodes and cathodes. 34 To reserve TEGDME with a volume ratio of 1:1 to Pyr 14 TFSI−2.0 M LiTFSI as a composite liquid component in the HSE, the drying time was controlled by monitoring the residual mass of the TEGDME solvent. After drying under vacuum and demolding from a Teflon mold, the HSE with a thickness of 70 μm comprising 60 wt % LLZTO, 33 wt % TEGDME− Pyr 14 TFSI (2.0 M LiTFSI), and 7 wt % PEO was prepared.…”