已传文件：photo/1773121782.png
The electrolytes for high-temperature lithium metal batteries designed through electrolyte engineering mainly include the following types:
Solvent-free molten salt electrolyte:
Composition: For example, a mixture of 45 wt.% LiFSI, 45 wt.% CsTFSI, and 10 wt.% LiTFSI (LCsL10). Characteristics:
High-temperature stability: The molten salt electrolyte has a low vapor pressure, which can expand the working temperature range of the battery and exhibit good thermal stability below 250°C.
SEI layer: A SEI layer rich in stable and tough LiF is formed on the lithium surface, effectively adapting to the volume changes of the lithium anode during the cycling process and inhibiting lithium dendrites and unnecessary side reactions even at high temperatures.
Electrochemical performance: At 80°C, with current densities of 0.5 and 1.0 mAh cm⁻², after 150 cycles, the average lithium deposition/striping coulomb efficiency reaches 99.4%.
High-concentration electrolyte:
Composition: For example, LiFSI/LiNO₃/TEGDME high-concentration electrolyte. Characteristics:
Solventized structure: The stability of the solventized structure is maintained through strong ion-dipole interactions, which slows down the lithium electrode deposition kinetics and inhibits the formation of lithium dendrites and dead lithium.
High-temperature performance: The LiFePO₄-Li battery using this electrolyte can cycle more than 120 times at 90℃ and more than 50 times at 100℃.
High-temperature liquid electrolyte:
Composition: For example, LiFSI and LiNO₃ are dissolved in a mixed solvent of FEC and TEGDM. Characteristics:
High-temperature feasibility: The Li|LiFePO₄ battery operating at 90℃ can achieve 100 cycles with a capacity retention rate of 91.5%.
SEI changes: High temperature causes incomplete decomposition of lithium salts and solvents, altering the composition of the SEI, but through electrolyte design, moderate SEI stability can be maintained.
Tri-component composite electrolyte additive system (PAFE):
Composition: Through the coordinated coordination of Al(EtO)₃ with fluoro-carbon vinylate (FEC) and ethoxy pentafluorocyclophosphonic anhydride (PFPN) molecules, a uniform solid-state electrolyte interface is formed. Characteristics:
High voltage stability: Enhances the cycling stability and safety of lithium metal batteries at a voltage of 4.7 V.
Preventing dendrites: Simultaneously alleviates the lattice stress of the ternary positive electrode and inhibits dendrites on the negative electrode.
Mixed salt electrolyte system:
Composition: For example, a mixed system of two electrolyte lithium salts, such as LiTFSI and LiODFB. Characteristics:
High-temperature compatibility: At 70℃, the compatibility of the ester-based electrolyte containing LiTFSI + LiODFB with aluminum foil was investigated, and the electrochemical performance of the Li/LiCoO₂ half-cell was tested.
Formation of CEI film: A uniform and dense CEI film was formed on the electrode surface to enhance the cycling stability of the battery.
