Immobilization of Anions on Polymer Matrices for Gel Electrolytes with High Conductivity and Stability in Lithium Ion Batteries

Abstract

TiO2 (to 6.5 V vs Li/Li(+)). Immobilization of PF6(-) anions also leads to the formation of stable solid-electrolyte interface (SEI) layers in a full-cell graphite|electrolyte|LiFePO4 battery, which exhibits low SEI and overall resistances. The graphite|electrolyte|LiFePO4 battery delivers high capacity of 84 mAh g(-1) even at 20 C and presents 90% and 71% capacity retention after 100 and 1000 charge-discharge cycles, respectively. This study demonstrates a GPE architecture comprising 3D space charge pathways for Li(+) ions and suppresses anion decomposition to improve the stability and lifespan of the resulting LIBs.

Recent Advancements in Polymer-Based Composite Electrolytes for Rechargeable Lithium Batteries

“…Up until now, numerous polymer/ liquid hybrid electrolytes along with the individual components have been studied and reported with equal intensity. These include polymer matrixes such as polyethylene oxide (PEO) and its derivate [73], poly(vinylidene fluoride) (PVDF) [74], poly(ethylene glycol) diacrylate (PEGDMA) [75], polymeric ionic liquid (PIL) and so on [76], as well as conventional liquid electrolytes and ionic liquids [77][78][79]. Here, the study of the liquid ingredients in polymer matrixes has been mainly devoted to the resolution of the diffusion issue as well as the realization of better interfacial adhesion between the two electrodes.…”

Minimization of Ion–Solvent Clusters in Gel Electrolytes Containing Graphene Oxide Quantum Dots for Lithium‐Ion Batteries

“…Gel polymer electrolytes (GPEs) are an alternative to SPEs because of their pseudo‐solid‐state nature along with an ionic conductivity as high as that of liquid‐state electrolytes . A salient advantage of GPEs over liquid‐state electrolytes is their readiness to modify polymer chains with functional groups, thereby promoting ion motion in the electrolyte bulk or at the electrode–electrolyte interface . Determining how the polymer functionalities, as well as their conjugation with an appropriate additive, can effectively alter the coordination of ions in the electrolyte to facilitate ion motion is a critical challenge for using GPEs to improve the performance of LIBs.…”

“…Copolymerizing PAN with PVAc, which contains protruding acetates for interaction with solvent molecules, facilitates ion transport and ensures the stability of GPEs. Poly(acrylonitrile‐ co ‐vinyl acetate) (PAV) represents an excellent backbone for the polymer host in GPEs . Integrating PMMA into PAV improves the electrode–electrolyte contact because the acrylate in PMMA is less obstructive to polymer chain rotation than the acetate in PVAc…”

“…The mechanical strength and electrochemical performance of the electrolytes have been shown to increase with a decrease in the size of fillers because of the improved filler distribution over the polymer network . Ceramic nanofillers exhibiting negative or positive zeta potentials in electrolytes have been used to immobilize anions or decrease the coordination between polymer and Li + ions . Lewis acid–base interactions between filler surface groups and ions appeared to be responsible for conductivity enhancement .…”

“…The clusters impede ion transport in the electrolyte bulk and obstruct ion transfer at the electrode–electrolyte interface. Figure b illustrates that the PAVM‐supported GPE (GPE‐PAVM) immobilizes the anions in the nitrile groups, resulting in the destruction of the ion–solvent clusters and formation of space‐charge layers that facilitate the transport of Li + ions . This cluster destruction lowers the degree of solvent coordination of Li + ions.…”