| Affiliation: | 1. College of Mechanical Engineering, Chengdu University, Chengdu, 610106 P. R. China
Institute for Advanced Study, Chengdu University, Chengdu, 610106 P. R. China;2. College of Mechanical Engineering, Chengdu University, Chengdu, 610106 P. R. China;3. Chongqing Academy of Metrology and Quality Inspection, Chongqing, 401121 P. R. China;4. Institute for Advanced Study, Chengdu University, Chengdu, 610106 P. R. China;5. Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu, 610065 P. R. China |
| Abstract: | Currently, the commercial separator (Celgard2500) of lithium-ion batteries (LIBs) suffers from poor electrolyte affinity, mechanical property and thermal stability, which seriously affect the electrochemical performances and safety of LIBs. Here, the composite separators named PVDF-HFP/TiN for high-safety LIBs are synthesized. The integration of PVDF-HFP and TiN forms porous structure with a uniform and rich organic framework. TiN significantly improves the adsorption between PVDF-HFP and electrolyte, causing a higher electrolyte absorption rate (192%). Meanwhile, XPS results further demonstrate the tight link between PVDF-HFP and TiN due to the existence of Ti? F bond in PVDF-HFP/TiN, resulting in a strong impediment for the puncture of lithium dendrites as a result of the improved mechanical strengths. And PVDF-HFP/TiN can effectively suppress the growth of lithium dendrites by means of uniform lithium flux. In addition, the excellent heat resistance of TiN improves the thermal stability of PVDF-HFP/TiN. As a result, the LiFePO4||Li cells assembled PVDF-HFP/TiN-12 exhibit excellent specific capacity, rate performance, and capacity retention rate. Even the high specific capacity of 153 mAh g?1 can be obtained at the high temperature of 80 °C. Meaningfully, a reliable modification strategy for the preparation of separators with high safety and electrochemical performance in LIBs is provided. |
