Solid polymer electrolytes(SPEs)have attracted extensive attention by virtue of lightweight and flexible processability for solidstate lithium metal batteries(LMBs)with high energy density and intrinsic safety.However...Solid polymer electrolytes(SPEs)have attracted extensive attention by virtue of lightweight and flexible processability for solidstate lithium metal batteries(LMBs)with high energy density and intrinsic safety.However,the SPEs suffer from the trade-off effect between ionic conductivity and mechanical strength.Herein,we report an ionic solid-like conductor with high Li+conductivity and good thermal stability as the conductive phase of polymer electrolytes for advanced LMBs.Using poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)as the polymer matrix,the ionic solid-like conductor can be regarded as a solid plasticizer due to its advantages of non-fluidity and non-leakage.It increases the amorphous region and the dissociation degree of lithium salts in SPEs,while minimizing the loss of mechanical properties.As a result,the Li+conductivity of SPEs incorporating the ionic solid-like conductor is enhanced by four orders of magnitude compared to the blank PVDF-HFPbased electrolyte.The optimized SPE membranes can be processed as thin as 50μm with a high Young's modulus of 16.8 MPa,therefore ensuring stable long-term cycling of solid-state LMBs.The Li/Li symmetric cells stably cycled for more than 750 h without short circuits,and the LiFePO_(4)/Li solid-state batteries demonstrate excellent electrochemical performance over 350cycles with a capacity retention of 82.5%.This work provides a new strategy for designing ionic solid-like conductors as solid plasticizers for high-performance polymer electrolytes.展开更多
基金supported by the National Key Research and Development Program of China(2023YFB2503700,and 2023YFC3008804)the National Natural Science Foundation of China(22071133)+1 种基金Beijing Municipal Science&Technology Commission(Z231100006123003)the Science Foundation of China Academy of Safety Science and Technology(2023JBKY17)。
文摘Solid polymer electrolytes(SPEs)have attracted extensive attention by virtue of lightweight and flexible processability for solidstate lithium metal batteries(LMBs)with high energy density and intrinsic safety.However,the SPEs suffer from the trade-off effect between ionic conductivity and mechanical strength.Herein,we report an ionic solid-like conductor with high Li+conductivity and good thermal stability as the conductive phase of polymer electrolytes for advanced LMBs.Using poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)as the polymer matrix,the ionic solid-like conductor can be regarded as a solid plasticizer due to its advantages of non-fluidity and non-leakage.It increases the amorphous region and the dissociation degree of lithium salts in SPEs,while minimizing the loss of mechanical properties.As a result,the Li+conductivity of SPEs incorporating the ionic solid-like conductor is enhanced by four orders of magnitude compared to the blank PVDF-HFPbased electrolyte.The optimized SPE membranes can be processed as thin as 50μm with a high Young's modulus of 16.8 MPa,therefore ensuring stable long-term cycling of solid-state LMBs.The Li/Li symmetric cells stably cycled for more than 750 h without short circuits,and the LiFePO_(4)/Li solid-state batteries demonstrate excellent electrochemical performance over 350cycles with a capacity retention of 82.5%.This work provides a new strategy for designing ionic solid-like conductors as solid plasticizers for high-performance polymer electrolytes.
