Layer-by-Layer Deposition of Organic–Inorganic Hybrid Multilayer on Microporous Polyethylene Separator to Enhance the Electrochemical Performance of Lithium-Ion Battery

A simple layer-by-layer (LbL) self-assembly process of poly(acrylic acid) (PAA) and ZrO2 was applied to construct functional ultrathin multilayers on polyethylene (PE) separators without sacrificing the excellent porous structure of separators. Such PAA/ZrO2 LbL-modified PE separators possess good electrolyte wettability, excellent electrolyte uptake, high ionic conductivity and large Li+ transference number. More importantly, the top layer of LbL self-assembly would affect the dissociation of electrolyte and the formation of solid electrolyte interphase (SEI) layer in half-cells. Compared with the pristine and (PAA/ZrO2)1PAA-modified PE separators, (PAA/ZrO2)3-modified PE separator shows a larger Li+ transference number (0.6) and a faster tendency to form a stable SEI layer, endowing half-cells with excellent capacity retention at high C-rates and superior cycling performance. These fascinating characteristics will provide the LbL self-assembly with a promising method to improve the surface property of PE separators for high performance lithium-ion batteries.