Developing Single‐Ion Conductive Polymer Electrolytes for High‐Energy‐Density Solid State Batteries

Abstract

Single‐ion conductive polymer electrolytes (SICPEs) with a cationic transference number (tLi+) close to unity exhibit specific advantages in solid‐state batteries (SSBs), including mitigating the ion concentration gradient and derived problems, suppressing the growth of lithium dendrites, and improving the utilization of cathode materials and the rate performance of SSBs. However, the application of SICPEs remains major challenges, i.e., the ionic conductivity is inferior at room temperature. Therefore, the recent accomplishments in improving the ambient ionic conductivity to be compatible SICPEs with a high transference number are discussed in this review. In particular, some strategies of delocalizing charges in polyanions, designing a highly conductive polymer matrix, and utilizing synergistic effects in SICPEs are focused to shed light on the further development of solid polymer electrolytes for SSBs. Finally, multifunctional species of SICPEs are discussed in view of the mechanical contact and/or charge transfer problems at the solid–solid interface in SSBs.

Polymer design for solid-state batteries and wearable electronics

“…2d and e). 81,82 This is promising as theoretical models suggest that t Li + close to unity, coupled with high shear-moduli that are roughly twice that of Li anodes , could suppress Li-dendrite growth (Fig. 2f).…”

“…Analyses of recent reviews on SLICs provided by Gao et al 81 and Lian and coworkers, 82 indicate that current best performances come from immobilised TFSI-like anions and, most recently, borates and aluminates. Early leading examples reported triblock polymers consisting of central PEO blocks with single-ion conducting lithium poly(styrene trifluoromethanesulphonylimide), P(STFSILi) blocks on either side.…”

Computational approach inspired advancements of solid-state electrolytes for lithium secondary batteries: from first-principles to machine learning

“…Compared to liquid and ceramic electrolytes, PEs, including solid polymer electrolytes (SPEs) and gel polymer electrolytes (GPEs), offer several advantages such as ease of processing, availability, and operational safety. 136,137 However, their widespread adoption is hindered by their relatively low ionic conductivity (around 10 −4 S cm −1 at 25 °C) and low Li + transference number (around 0.3). 138 Overcoming these limitations is crucial to match the performance of state-of-the-art electrolytes, and it requires a deep understanding of the Li-ion conduction mechanisms in polymer electrolytes.…”

Functionally Modified Polymer Electrolyte Based on Noncovalent Interaction for Stable Lithium Metal Batteries

“…However, the ionic conductivity of most single-ion conducting polymer electrolytes is usually lower than their theoretical values, mainly due to the anionic structural units attached to the polymer chains that limit the movement and stretching of the chains. − To avoid the above problems, we tried to limit the anion migration as much as possible by forming a weak intermolecular force between the polymer and the anion, thus acting as a constraint on the anion migration and diffusion between the molecular chains without affecting the Li + conduction through the flexible segments. , In this work, a functional modified polymer electrolyte (P­(DEGDA–TFS)/PVDF FMPE) with selective cation transport was designed and synthesized by copolymerizing 4-(trifluoro­methyl)­styrene (TFS) side groups on the poly­(diethylene glycol diacrylate) (PDEGDA) chain for functionalization. A combination of first-principles density functional theory (DFT) calculations and electrochemical tests revealed the different facilitating roles of Li + transport played by the TFS functionalized side groups.…”