Separator porous skeleton regulation dependency on lithium-ion and lithium-metal battery performances

Abstract

Building separator porous skeletons that suit lithium-ion and lithium-metal batteries (LIBs and LMBs) remains challenging since battery assembly and operation degrade separator mechanical-chemical stabilities inevitably. To fabricate separators with industrial considerations and battery compatibility, herein, the effect of intrinsic porous skeletons on separator mechanical/chemical stabilities and subsequent LIB or LMB performances are clarified based on uncovering integrated porous skeleton formation mechanisms. Lamellae separation and slip dominate longitudinal drawing, severally generating inter-fibril defects and inner-fibril lamellae. Transverse drawing sequentially compels inter-fibril defects to split, which deflects inner-fibril lamellae and enlarges pores. Homogenized lamellae dispersions thus exhibit unique advantages, maximizing fibrous refinement and uniformizing porous skeletons. This superior porous skeleton with smoother linearity facilitates homogeneous Li+ fluxes, stabilizes Li plating-stripping, and enables improved battery performances, especially at high currents, indicating more suitable with high-power density batteries and fast charging technologies. The dependency clarifications of separator fabrication-structure-function lend theoretical guidance for fabricating and choosing ideal porous skeletons for not only LIBs and LMBs but also the other prospective rechargeable batteries.