In-Situ-Polymerized 1,3-Dioxolane Solid-State Electrolyte with Space-Confined Plasticizers for High-Voltage and Robust Li/LiCoO₂ Batteries

Abstract

In-situ-polymerized solid-state electrolytes can significantly improve the interfacial compatibility of Li metal batteries. Typically, in-situ-polymerized 1,3-dioxolane electrolyte (PDOL) exhibits good compatibility with Li metal. However, it still suffers from the narrow electrochemical window (4.1 V), limiting the application of high-voltage cathodes. Herein, a novel modified PDOL (PDOL-F/S) electrolyte with an expanded electrochemical window of 4.43 V and a considerable ionic conductivity of 1.95 × 10–4 S cm–1 is developed by introducing high-voltage stable plasticizers (fluoroethylene carbonate and succinonitrile) to its polymer network. The space-confined plasticizers are beneficial to construct a high-quality cathode–electrolyte interphase, hindering the decomposition of lithium salts and polymers in electrolytes at high voltage. The as-assembled Li|PDOL-F/S|LiCoO2 battery delivers superior cycling stability (capacity retention of 80% after 400 cycles) at 4.3 V, superior to that of pristine PDOL (3% after 120 cycles). This work provides new insights into the design and application of high-voltage solid-state lithium metal batteries by in situ polymerization.

In Situ Solid-State DETFPi-PDOL Electrolyte and Its Impact on the Interfaces and Performance of NCM811||Li Batteries

“…However, PDOL lacks sufficient oxidation resistance, and its interfacial compatibility with high-voltage cathodes (cutoff voltage ≥4.2 V, such as NCM cathode) is poor. , Constructing a uniform and stable CEI layer on the surface of the cathodes can significantly improve the PDOL/cathode interfacial compatibility. Guo and co-workers used triphenylphosphine (TPP) to construct a stable CEI layer on the surface of the NCM cathode, achieving the stable cycling of PDOL-EC/DEC/DMC electrolyte for 100 times in NCM622||Li battery; Li and co-workers introduced fluoroethylene carbonate (FEC) and hexamethylene diisocyanate (HDI) into PDOL to construct a stable interface under high voltage, getting the cycling performance of LiCoO 2 ||Li batteries at 4.2 V improved; Sun and co-workers used aluminum isopropoxide (AIP) as an interfacial additive to improve the interfacial stability in PDOL/NCM811 and achieved stable cycling of NCM811||Li batteries at 4.3 V. Presently, one of the problems with PDOL system is, although the additives used can only achieve single interfacial modification, it cannot simultaneously improve the stability of PDOL at cathode/anode interfaces to further enhance the performance of high-voltage lithium metal batteries.…”

An Intelligent “Solid–Liquid” Hybrid Electrolyte for High-Voltage and Dendrite-Free Lithium Metal Batteries

“…1,3-Dioxolane (DOL), which is one of the most commonly used monomers for in situ polymerization, is susceptible to Lewis acid-initiated ring-opening polymerization. − Nevertheless, similar to other polyether-based electrolytes, the room temperature (RT) ionic conductivity of the poly­(1,3-dioxolane) (PDOL) electrolyte is only 10 –6 S cm –1 , which hinders its practical application . Inhibiting the conversion of a portion of DOL monomers into solid electrolytes will improve ionic conductivity .…”

An initiator loaded separator triggering in situ polymerization of a poly(1,3-dioxolane) quasi-solid electrolyte for lithium metal batteries

“…Generally, the initiator is directly dissolved in the DOL precursor solution, and then the mixed solution is injected into the cell for in situ polymerization. 37 It should be noted that DOL can be polymerized even at room temperature since the concentration of the initiator is high enough, which may lead to partial solidification of the precursor solution prior to cell assembling, resulting in an inhomogeneous GPE and an imperfect interface. Consequently, the cell performance needs to be improved further by optimizing the distribution route of the initiator.…”