Separator membranes, a critical component of lithium-ion batteries, are responsible for storing the electrolyte, facilitating the transport of lithium ions between the positive and negative electrodes, and preventing internal short circuits, thus playing a vital role in the safety of these batteries [9, 10, 11, 12, 13].
As the vital roles such as electrodes, interlayers, separators, and electrolytes in the battery systems, regulating the membrane porous structures and selecting appropriate membrane materials are significant for realizing high energy density, excellent rate capability, and long cycling stability of lithium rechargeable batteries (LRBs).
An overview and analysis of the state of the art on lithium ion battery separators is presented for the different separator types, including microporous membranes, nonwoven membranes, electrospun membranes, membranes with external surface modification, composite membranes and polymer blends.
Li MX, Wang XW, Yang YQ, Chang Z, Wu YP (2015b) A dense cellulose-based membrane as a renewable host for gel polymer electrolyte of lithium ion batteries. J Membr Sci 476:112–118. doi: 10.1016/j.memsci.2014.10.056
More importantly, the asymmetric porous structured membrane with a dense layer can act as an active material and current collector, avoiding the use of separate current collectors, even conductive agents and binders in lithium-ion battery, which is beneficial for superior electrochemical performances in terms of high reversible capacity.
Generally, lithium metal-based batteries are composed of a cathode, anode, separator, and electrolyte.