Ionic Liquid Functionalized Gel Polymer Electrolytes for Stable Lithium Metal Batteries

Abstract

Metallic lithium (Li)i sr egarded as the ideal anode material in lithium-ion batteries due to its low electrochemical potential, highest theoretical energy density and low density. There are,however,still significant challenges to be addressed such as Li-dendrite growth and low interfacial stability,which impede the practical application of Li metal anodes.Inorder to circumvent these shortcomings,h erein, we present ag el polymer electrolyte containing imidazolium ionic liquid end groups with aperfluorinated alkyl chain (F-IL) to achieve both high ionic conductivity and Li ion transference number by fundamentally altering the solubility of salt within the gel electrolyte through Lewis-acidic segments in the polymer backbone.M oreover,t he presence of F-IL moieties decreased the binding affinity of Li cation towards the glycol chains, enabling ar apid transfer of Li cation within the gel network. These structural features enabled the immobilization of anions on the ionic liquid segments to alleviate the space-charge effect while promoting stronger anion coordination and weaker cation coordination in the Lewis-acidic polymers.Accordingly, we realized ahigh Li ion conductivity (9.16 10 À3 Scm À1 )and high Li ion transference number of 0.69 simultaneously,along with ag ood electrochemical stability up to 4.55 V, while effectively suppressing Li dendrite growth. Moreover,t he gel polymer electrolyte exhibited stable cycling performance of the Li j Li symmetric cell of 9mAh cm À2 for more than 1800 hours and retained 86.7 %ofthe original capacity after 250 cycles for lithium-sulfur (Li-S) full cell.

Design of a multi-functional gel polymer electrolyte with a 3D compact stacked polymer micro-sphere matrix for high-performance lithium metal batteries

“…[19][20][21][22][23] To enhance the ionic conductivities of solid polymer electrolytes, liquid electrolytes are usually introduced to obtain gel polymer electrolytes (GPEs). [24][25][26] However, in the case of single ion conductors, only organic liquids are needed to form GPEs, as lithium salts have already been xed onto the polymer chains. [27][28][29][30] Unlike pure solid polymer electrolytes in which the polymer hosts must not only provide solvation groups such as ethylene oxide (EO) segments in polyethylene oxide (PEO), propylene oxide (PO) in poly(propylene oxide) (PPO), etc., to dissociate lithium salts but also offer low glass transition temperature to facilitate ion migration within the polymer matrix to exhibit high ionic conductivities, GPEs are more exible in selecting the polymer matrices, as the ionic conductivity is mainly dominated by the liquid electrolyte in GPEs.…”

Interfacial Electrochemistry-Induced Detachable Adhesives with Ultra-High Bonding Strength and Detaching Efficiency

“…Ionic liquids (ILs) are a new, innovative class of solvents with free organic cations and counterions . Based on the excellent physicochemical properties including high ionic conductivity, good wetting ability, nonvolatility, and a wide range of melting points, ILs have demonstrated tremendous potential in developing reversible ionogel adhesives.…”

“…Ionic liquids (ILs) are a new, innovative class of solvents with free organic cations and counterions. 31 ILs can be used to develop adaptable adhesives by immobilizing ionic crystals (ICs) onto soft polymer chains. 17,18 Due to the excellent wettability of melted ILs and crystalreinforced high cohesive strength, the as-prepared adhesives show a high bonding strength of 5.82 MPa.…”

Approaching Practically Accessible and Environmentally Adaptive Sodium Metal Batteries with High Loading Cathodes through In Situ Interlock Interface

“…[18][19][20] Moreover, the incorporation of glycol chains into GPE has considerable potential to facilitate the relatively homogeneous ion flux and further mitigate the dendrite growth to control the surface microstructure of the metal anode. [21] Unfortunately, this protective effect, which is related to the chemistry and structure of SEI, is not yet comprehensively understood for SMBs, especially at low temperatures. In addition, considering the practical battery assembly requirements, with the cathode loading increased, it is difficult for GPE to fully penetrate into the thick cathode due to its high interfacial impedance, resulting in the fragmentary ionic conducting network.…”