Regulation of Li-ion flux by metal organic framework in compact quasi-solid-state electrolyte for wide-temperature lithium-metal batteries

The practical application of lithium metal anodes is hindered by uncontrolled growth of lithium dendrites, which can ulteriorly exacerbate at low or high temperature. To address these issues, a dense quasi-solid-state electrolyte (CPLZ) operating at wide-temperature-range is prepared based on cellulose acetate (CA) and polyvinylidene fluoride (PVDF) as polymer matrices, metal organic framework (ZIF-8) as nanofiller, LiTFSI as Li-ion source. The Raman spectra confirms the strong interaction between ZIF-8 and TFSI − and FTIR spectra verifies ZIF-8 weakens the adsorption of Li + on CA, which can promote Li salt dissociation, accelerate the Li + transport and regulate the Li + flux, thereby facilitating uniform lithium deposition. Meanwhile, the addition of ZIF-8 greatly improves dendrite suppression by enhancing CPLZ's mechanical strength. The obtained CPLZ electrolyte exhibits a high ionic conductivity over a wide temperature range (6.9 × 10 −4  S cm −1 at room temperature), a high ion migration number (0.57 at room temperature) and achieves the stable and reversible lithium deposition and stripping over 400 h. Furthermore, the assembled Li|CPLZ|LiFePO 4 cells exhibit the discharge-capacity of 133.9 mA h g −1 at 3C after 400 cycles at room temperature. Most importantly, thanks to high ion transport and interface stability, the Li|CPLZ|LiFePO 4 batteries exhibit an excellent wide-temperature-range operation with stable cycling over 500 cycles with the discharge-capacity of 138.1 mA h g −1 at 1C at 60 °C and the capacity retain up to 60 % of room temperature at −15 °C. This research provides valuable insights for advancing lithium metal batteries characterized by enhanced safety and prolonged cycle stability at wide-temperature-range.