Highly Stretchable and Elastic Polymer Electrolytes with High Ionic Conductivity and Li‐Ion Transference Number for High‐Rate Lithium Batteries

Abstract

Comprehensive SummaryThe ever‐growing demand for wearable electronics drives the development of stretchable lithium‐ion batteries (LIBs) with fast charging capability, in which stretchable polymer electrolytes (PEs) with high ionic conductivity and lithium‐ion transference numbers () are highly desirable. Herein, we report a highly stretchable and elastic PE with high ionic conductivity and , which is applicable in high‐rate and stretchable LIBs. The PE was fabricated by incorporating polyethylene glycol (PEG) and lithium salts into polyurethane networks, wherein α‐cyclodextrin (α‐CD) acts as the cross‐linker. The PEG chains are cross‐linked by covalent and noncovalent bonds, and some PEG chains enter into the cavity of α‐CD to form PEG/α‐CD inclusions. These structural features effectively suppress crystallization of the PEG chains, hinder movement of the counterions of Li+, and endow PE with satisfactory mechanical robustness. The PE with a tensile strength (0.61 MPa) exhibits a large strain at break (840%) and excellent elasticity, possessing a high ionic conductivity (5.0 × 10–4 S·cm–1) and a high (0.52). The Li‖LiFePO4 battery assembled with the PE delivers a high capacity of 75 mAh·g–1 even at the high rate of 16 C. The battery can be stably cycled for 300 and 200 cycles at 1 C and 4 C, respectively.

Polyrotaxane‐Based Functional Materials Enabled by Molecular Mobility and Conformational Transition†

“…[ 139 ] In other areas of batteries besides binders, especially separator materials that require rapid proton exchange, polyrotaxane‐based materials have also received a lot of attention. [ 140‐143 ] Overall, the innovative universal material design strategy based on slide‐ring structures is expected to improve battery performance in the future, and the binder concept proposed by Choi and colleagues could be used to improve the electrochemical performance of materials with a large volume change, for lithium‐ion batteries and other applicaions.…”

Quasi‐Solid‐State Composite Electrolytes with Multifunctional 2D Molecular Brush Fillers for Long‐Cycling Lithium Metal Batteries†

“…A low easily increases the electrode polarization and leads to poor electrochemistry performance, so improving the of QSCEs is of great significance for LMBs. [ 36 ] The of QSPE‐PH/P is only as low as 0.32 (Figure S8a). With the introduction of GO and GO‐ g ‐PFIL fillers, the of QSCE‐PH/GO3/P and QSCE‐PH/GPFIL3/P increases to 0.46 and 0.82 (Figures 4c and S8b), respectively.…”

Block Copolymer Solid Electrolytes Based on Comb‐Like Poly(ethylene glycol) Plasticized Poly(ionic liquid)s for Lithium‐Ion Batteries†

“…[ 4‐5 ] In order to solve these problems, solid polymer electrolytes (SPEs) with non‐flammability, higher thermal stability and non‐leakage are getting more and more attention from both academic and industry fields. [ 6‐7 ] So far, SPEs based on polyethylene oxide (PEO), [ 8‐11 ] polyacrylonitrile (PAN), [ 12‐14 ] polyvinylidene fluoride (PVDF), [ 15‐17 ] polycarbonate [ 18‐19 ] and polymerized ionic liquids (PILs) [ 20‐23 ] have been widely studied. Specifically, PILs have attracted great interest owing to their robust electrochemical stability, [ 24 ] high security, [ 25 ] processability [ 24‐25 ] and facile modification of molecular structure.…”