Inorganic Chemicals Industry ›› 2021, Vol. 53 ›› Issue (11): 42-48.doi: 10.19964/j.issn.1006-4990.2021-0389

• Research & Development • Previous Articles     Next Articles

Study on chemically crosslinked polyimide separators for lithium-ion batteries with enhanced performance

YUAN Biao(),SHI Yake,CHEN Zan   

  1. CenerTech Tianjin Chemical Research and Design Institute Co.,Ltd.,Tianjin 300131,China
  • Received:2021-06-28 Online:2021-11-10 Published:2021-11-15

Abstract:

As an important part of lithium-ion batteries,separators are used to block the direct contact between cathode and anode and provide an effective channel for lithium ion transmission between electrodes.Polyimide separators have been wide-ly concerned because of their long charge-discharge cycle life,moderate mechanical strength,good electrical insulation and self extinguishing ability.Polyimide separators were chemically crosslinked by using p-dimethylamine as crosslinking agent,the structure-activity relationship between the crosslinking time and the morphology,structure and properties of separators was studied.With the increase of crosslinking time,the porosity and liquid absorption rate of separators decreased,and the contact angle of the electrolyte and mechanical strength increased gradually.Electrochemical tests showed that with the increase of crosslinking time,the bulk impedance of separators increased gradually and the ionic conductivity decreased gradu-ally.The interfacial resistance of crosslinked separators was much lower than that of uncrosslinked separators,and the electro chemical window of crosslinked separators was also broader than that of uncrosslinked separators.The test result of assembling half cell showed that the rate performance and cycle performance of battery assembled by crosslinked separators were better than those of uncrosslinked separators.When the crosslinking time was 48 h,the performance of battery was best.After 100 charge-discharge cycles,the specific discharge capacity was 130.2 mA·h/g and the capacity retention rate was 91.1%.

Key words: lithium-ion battery, polyimide, separators, crosslinked

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