A Highly-Efficient Composite Separator with Strong Ligand Interaction for High-Temperature Lithium-Ion Batteries

A PVDF-HFP/colloidal-TiO2 composite separator is synthesized for high-temperature lithium-ion batteries. Incorporation of colloidal TiO2 in the PVDF-HFP matrix forms a highly-uniform composite micro-structure with strong adsorption interactions between TiO2 and PVDF-HFP due to the presence of citric acid. The strong interactions are giving rise to advantageous mechanical robustness, separator/electrode interface and electrolyte uptake. The separator shows remarkable stability upon thermal treatment at 150 degrees C. With a high ionic conductivity up to 1.57 x 10(-3) Scm(-1), the LFP/Li cell with PVDF-HFP/colloidal-TiO2 composite separator delivers charge-discharge capacities of 156.95 mAhg(-1) (0.1 C) at room temperature and 120.8 mAhg(-1) (0.5 C) after annealing cells at 140 degrees C for 3 hours with a 99% capacity retention after 100 cycles. The PVDF-HFP/colloidal-TiO2 separator demonstrates promising potentials for practical applications in high-temperature environments.