Separator modification represents a critical strategy for addressing the challenges in lithium-ion batteries(LIBs),including restricted Li^(+) transport,poor interfacial stability,and safety risks.Using functional coa...Separator modification represents a critical strategy for addressing the challenges in lithium-ion batteries(LIBs),including restricted Li^(+) transport,poor interfacial stability,and safety risks.Using functional coatings has emerged as an effective approach for enhancing separator performance without altering the bulk structure of the separators.Herein,we report the first example of ethynylene-linked conjugated microporous polymers(CMPs)for LIB separator modification.Specifically,two CMPs substituted with different groups(fluorine for CMP-F and methyl for CMP-CH_(3))were synthesized through dynamic alkyne metathesis and applied as functional coatings on polyethylene(PE)separators.The ethynylene-linked backbone structure,along with the introduction of electron-withdrawing fluorine atoms,endows the CMPs with high electron density,hence reducing Li^(+) binding and solvent interactions,lowering the desolvation energy barrier at the electrolyte-separator interface,and facilitating Li^(+) transport.The fluorine could also act as hopping sites to facilitate Li^(+) conduction.We demonstrated through full-cell evaluations using graphite anodes and NMC532 cathodes that CMP-F@PE separators significantly improve both the rate performance and cycling stability.Furthermore,the CMP-F@PE separators also exhibited outstanding thermal stability,thereby improving battery safety.These results highlight the great potential of ethynylene-linked CMPs as structurally tunable,superior-performance,high-efficiency separator coatings for next-generation LIBs.展开更多
文摘Separator modification represents a critical strategy for addressing the challenges in lithium-ion batteries(LIBs),including restricted Li^(+) transport,poor interfacial stability,and safety risks.Using functional coatings has emerged as an effective approach for enhancing separator performance without altering the bulk structure of the separators.Herein,we report the first example of ethynylene-linked conjugated microporous polymers(CMPs)for LIB separator modification.Specifically,two CMPs substituted with different groups(fluorine for CMP-F and methyl for CMP-CH_(3))were synthesized through dynamic alkyne metathesis and applied as functional coatings on polyethylene(PE)separators.The ethynylene-linked backbone structure,along with the introduction of electron-withdrawing fluorine atoms,endows the CMPs with high electron density,hence reducing Li^(+) binding and solvent interactions,lowering the desolvation energy barrier at the electrolyte-separator interface,and facilitating Li^(+) transport.The fluorine could also act as hopping sites to facilitate Li^(+) conduction.We demonstrated through full-cell evaluations using graphite anodes and NMC532 cathodes that CMP-F@PE separators significantly improve both the rate performance and cycling stability.Furthermore,the CMP-F@PE separators also exhibited outstanding thermal stability,thereby improving battery safety.These results highlight the great potential of ethynylene-linked CMPs as structurally tunable,superior-performance,high-efficiency separator coatings for next-generation LIBs.
