Functional Applications of Polymer Electrolytes in High‐Energy‐Density Lithium Batteries

Abstract

Polymer electrolytes have attracted great interest in advanced lithium batteries. Recently, it has been found that there are many functional applications of polymer electrolytes in lithium batteries, which are very important for the development of high-energy-density lithium batteries. In this review, the functional applications of polymer electrolytes are reviewed in terms of protecting lithium metal anode, coating for high-voltage cathodes, and improving the safety of batteries. Finally, the remaining challenges and future perspectives of polymer electrolytes in these functional applications are presented. This review aims to provide a comprehensive understanding of polymer electrolytes and promotes their functional application in high-energy-density lithium batteries.

Lignin–Chitosan Gel Polymer Electrolytes for Stable Zn Electrodeposition

“…On the contrary, as schematized in Figure b, LSKL–chitosan and LS–chitosan GPEs show a semi-ductile behavior characterized by E values ranging from 55 ± 4 to 940 ± 63 MPa and ε b values of 14.1 ± 0.2 to 43.9 ± 21.1% (Figure c,d). For the sake of comparison, the most widely exploited GPE, the polyethylene oxide/LiTFSI blend, displays a Young’s modulus of ∼100 MPa . Independently of the composition, we found that glutaraldehyde cross-linking increases stiffness and lowers ductility due to the formation of extended imine linkages in the electrolyte.…”

“…For the sake of comparison, the most widely exploited GPE, the polyethylene oxide/LiTFSI blend, displays a Young's modulus of ∼100 MPa. 15 Independently of the composition, we found that glutaraldehyde cross-linking increases stiffness and lowers ductility due to the formation of extended imine linkages in the electrolyte. An increased fraction of lignin lowers both E and ε b values as reported for chitosan-lignin films, 49,50 while the micellar LSKL dispersion results in stiffer but more brittle GPEs in comparison with LS−chitosan GEPs.…”

“…14 The separator−electrolyte pair is a relevant battery component because it determines to a large extent its electrochemical performance (energy density or cycle stability) and safety (thermal stability or resistance against dendrite puncture). 15 This component must ensure adequate ion transference between electrodes at the same time that electronically and physically insulates the anode and the cathode so that internal short circuits and eventual ignition or explosion risks are avoided. 16 The substitution of the porous non-renewable separator soaked into an aqueous electrolyte by a gel polymer electrolyte (GPE) is now pursued by both academia and industry to enhance battery safety by avoiding electrolyte leakage.…”

“…The separator–electrolyte pair is a relevant battery component because it determines to a large extent its electrochemical performance (energy density or cycle stability) and safety (thermal stability or resistance against dendrite puncture) . This component must ensure adequate ion transference between electrodes at the same time that electronically and physically insulates the anode and the cathode so that internal short circuits and eventual ignition or explosion risks are avoided .…”

Phosphonate-Functionalized Ionic Liquid Gel Polymer Electrolyte with High Safety for Dendrite-Free Lithium Metal Batteries

“…Energy density and safety performance have become two bottle-neck issues for the state-of-the-art lithium-ion battery technology along with its explosive applications in energy storage grids and electric vehicles. − The replacement of graphite anode with lithium metal creates a huge space to lift the energy density because of the superior theoretical capacity of lithium (3860 mA h g –1 ) compared to graphite (370 mA h g –1 ). , However, there are four safety problems in the lithium metal anode, including dendrite growth, migratory intermediate species, unstable SEI layer, and infinite volume change . Among them, the formation of lithium dendrite is considered to be the main reason for the failure of the lithium metal anode, which causes short circuit .…”