非对称复合隔膜的制备及其锂金属电池性能研究OA

Lithium metal batteries are promising candidates for next-generation energy storage systems due to their exceptionally high theoretical energy density.However,the commercial application of polyolefin separators is limited as they exhibit poor thermal stability,low lithium-ion transference numbers,and limited ability to suppress lithium dendrite growth.In this study,polyethylene(PE)was used as the base membrane,and an asymmetric coating strategy was employed to construct a Janus-structured PPL composite separator.A rigid PAN@LATP layer and a flexible PEO-SiO2 layer were introduced on opposite sides of the membrane.LATP and SiO2 nanoparticles provide strong anion anchoring,weakening the Coulombic interactions between Li+and anions and increasing the lithium-ion transference number from 0.38 for the PE separator to 0.8.The asymmetric structure,combining rigidity and flexibility,imparts a mechanical strength of 95 MPa and a high voltage tolerance of up to 5.0 V.It also promotes uniform ion flux and effectively suppresses lithium dendrite growth.Electrochemical testing demonstrated that a Li||Li symmetric cell assembled with the PPL separator achieved stable cycling for 1000 h at 0.5 mA/cm2,whereas the PE separator system failed due to short circuiting after 300 h.Furthermore,the assembled LFP||Li cell exhibited an initial discharge capacity of 163.25 mAh/g at 1 C and retained 93%of its capacity after 200 cycles,significantly outperforming the PE separator system(69.2%).This asymmetric composite separator,with its interface-specific functional design,offers an effective strategy for improving the safety and cycling stability of lithium metal batteries.