Healable, Highly Conductive, Flexible, and Nonflammable Supramolecular Ionogel Electrolytes for Lithium-Ion Batteries

Abstract

High-performance solid-state electrolytes with healability to repair mechanical damages are important for the fabrication of Li-ion batteries (LIBs) with enhanced safety and prolonged service life. In this study, we present the fabrication of healable, highly conductive, flexible, and nonflammable ionogel electrolytes for use in LIBs by loading ionic liquids and Li salts within a hydrogen-bonded supramolecular poly(ionic liquid) copolymer network. The ionogel electrolytes exhibit ionic conductivities as high as 10 −3 S/cm, which is comparable to the conventional liquid electrolytes. The Li/LiFePO 4 battery assembled with the ionogel membrane exhibits excellent cycling performance and delivers a steady high discharge capacity of 147.5 mA h g −1 and Coulombic efficiency of 99.7% after 120 cycles at the charge/discharge rate of 0.2 C. Importantly, the ionogel membranes can heal damages outside or inside a battery because of the reversible nature of the supramolecular interactions between the components. The damaged ionogel membranes after being healed can effectively restore the original performance of the LIBs.

Self‐Healing Materials for Energy‐Storage Devices

“…In order to have higher ionic conductivity at room temperature, Sun and co‐workers [ 128 ] synthesized an imidazolium‐based UPy‐containing polymeric ionic liquids (PIL‐UPy, Figure a) and fabricated the ionogel membrane electrolyte comprising of PIL‐UPy, 1,2‐dimethyl‐3‐ethoxyethyl imidazolium bis(trifluoromethanesulfonyl)imide (DE‐IM/TFSI) and LiTFSI (Figure 10b). The ionogel membrane electrolyte presented good flexibility, high ionic conductivity of 10 −3 S cm −1 , and excellent nonflammability (Figure 10c).…”

“…d) Photos of the ionogel membranes that were cut into two pieces and then healed inside a LiFePO 4 ||Li button cell at 55 °C for 1 h. Reproduced with permission. [ 128 ] Copyright 2019, ACS Publications. Chemical structure of e) PAA‐UPy supramolecular polymer and f) UPy‐UPy dimers.…”

Overview of Ionogels in Flexible Electronics

“…Guo et al [158] prepared an ionogel by random pre-polymerization of two ILs. One of ILs bears ureido-pyrimidinone (UPy) pendant groups (IL-UPy), another bears an ethoxyethyl (IL-ether).…”

Flourishing Self‐Healing Surface Materials: Recent Progresses and Challenges

“…Nowadays, it is a great interest to focus on energy conversion devices with long lifespan and high efficiencies, such as batteries, solar cells, nanogenerators, and other energy conversion devices ( Figure a–c). Nevertheless, in a practice environment, the stability and power transfer efficiency possibly decrease because these devices are susceptible to the defects and surface damages upon the harsh environment. For example, the occurrence of microcracks and scratches on the surface of solar cells not only reduce the power conversion efficiency but also cause safety concerns .…”