Poly(vinylidene fluoride) (PVDF) gel polymer electrolytes (GPEs) show great potential for application in lithium-ion batteries (LIBs) due to their outstanding characteristics. However, the inferior thermal stability and low ionic conductivity limit their practical application. Herein, γ-LiAlO2 was synthesized and applied in a polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP)-polybenzimidazole containing an ether bond (OPBI)-polyoxyethylene (PEO) (PHOP-LAO) GPE for improving its thermal stability and ionic conductivity properties. The ionic conductivity of PHOP-LAO is 4.83 mS cm–1, which increased by 210% compared with that of the PHOP sample. It is worth noting that the thermal shrinkage of the PHOP-LAO membrane is greatly reduced (less than 1% at 230 °C for 1 h). PHOP-LAO shows outstanding thermal stability, which is beneficial for the safety of LIBs. When the PHOP-LAO GPE was applied to LIBs with Li1.04Ni1/3Co1/3Mn1/3O2 as a cathode, the LIBs exhibit remarkable and stable cycling performance with a discharge capacity retention rate of 85% after 500 cycles at a 2 C rate and maintain a power capability retention rate of up to 77% of the initial capability at the high rate of 10 C (50 °C). PHOP-LAO thus shows great potential for achieving ultra-stable and safe LIBs in the future.
The prelithiated SiO x anode showcases markedly improved Li-storage capabilities compared to its unlithiated counterparts, yet it faces hurdles such as slurry gassing, electrolyte deterioration, and capacity fade attributed to residual alkali and an unstable electrolyte/anode interface. To tackle these challenges, we propose a strategic utilization of residual alkali by creating an in-situ γ -LiAlO 2 functional layer on the prelithiated SiO x @C anode material. This is accomplished by incorporating a minor amount of Al 2 O 3 into the SiO x @C/LiH precursor mixture before the solid-phase prelithiation process. The resulting modified prelithiated SiO x @C anode with in-situ formed electrolyte-isolating γ -LiAlO 2 layer exhibits no discernible slurry gas generation within 7 days and substantially mitigates side reactions with the electrolyte, thereby boosting the initial coulombic efficiency and cycling stability of the SiO x @C anode. In half-cell evaluations, the prelithiated SiO x @C anode demonstrates a high Li-storage capacity of 1323 mAh g −1 and an impressive initial coulombic efficiency of 91.09%. When assessed in a 3.2 Ah 18650 cylindrical battery, the prelithiated SiO x @C anode showcases exceptional cyclability, retaining 81% of its capacity after 1000 cycles, underscoring its potential for practical applications. This study introduces a scalable and cost-effective prelithiation technique that propels the development and practical deployment of Si-based anodes by resolving persistent scientific challenges with the use of inexpensive additives.
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