Regulation of Interphase Layer by Flexible Quasi‐Solid Block Polymer Electrolyte to Achieve Highly Stable Lithium Metal Batteries

Abstract

Low safety, unstable interfaces, and high reactivity of liquid electrolytes greatly hinder the development of lithium metal batteries (LMBs). Quasi‐solid‐state electrolytes (QGPEs) with superior mechanical properties and high compatibility can meet the demands of LMBs. Herein, a biodegradable polyacrylonitrile/polylactic acid‐block‐ethylene glycol polymer (PALE) as membrane skeleton for GPEs is designed and systematically investigated by regulating the length and structure of the cross‐linked chain. Benefiting from the enriched affinitive sites of polar functional groups (CO, COC, CN, and OH) in highly cross‐linked polymer structure, the designed PALE membrane skeleton exhibits flame‐retardant property and ultrahigh liquid electrolyte uptake property, and the derived quasi‐solid‐state PALE GPEs deliver enhanced stretchability and a higher electrochemical stable window of 5.11 V. Besides, the PALE GPEs effectively protect cathodes from corrosion while allowing uniform and fast transfer of Li+ ions. Therefore, the Li||Li symmetrical battery and LFP or NCM811||Li full‐cell using PALE GPEs exhibit excellent cycling stability coupled with compact and flat inorganic/organic interface layers. And the excellent cycling stability of pouch cells under harsh operating conditions indicates the application possibilities of PALE GPEs in flexible devices with high‐energy‐density.

Waste for Waste: Interface-Intensified Durable Superhydrophilic–Superoleophobic Collagen Fiber Membrane for Efficient Separation of Cationic Surfactant-Stabilized Oil-in-Water Emulsions

“…Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were employed for this purpose. The FT-IR analysis (Figure b) revealed shifts in the peaks corresponding to the CO symmetric stretching and CC stretching. − Specifically, after the emulsion separation, the peaks shifted from 1632 to 1639 cm –1 and from 1547 to 1536 cm –1 , respectively, compared to fresh CFM–PMDA–TiO 2 . Additionally, the intensities of both peaks decreased, indicating the involvement of PMDA in the reaction process.…”

“…Furthermore, the XPS analysis (Figure 5c) was used to investigate changes in the surface chemical state of the CFM−PMDA− TiO 2 before and after emulsion separation. The observation of minimal changes in the Ti peak indicated that the structure of TiO 2 remained intact 38 (Figure S14). This change may be attributed to the involvement of titanium in the demulsification process.…”

Solid-state polymer electrolytes in lithium batteries: latest progress and perspective

“…It lacks oxygen atoms, and the nitrogen atom in PAN does not strongly interact with lithium ions. Its ionic conductivity can reach 3 mS cm −1 while possessing an electrochemical window exceeding 4.5 V. 159–163 However, due to its low strength and poor mechanical properties, PAN has been used predominantly utilized as a gel polymer electrolyte (GPE) for a long period. 164…”

A Review of the Relationship between Gel Polymer Electrolytes and Solid Electrolyte Interfaces in Lithium Metal Batteries

“…The functional group of the GPE polymer substrate is electronegative and can form a solvated structure of lithium ions, which is conducive to the uniform deposition of lithium ions. Chai et al [124] prepared PALE GPEs using polyacrylonitrile/polylactic acid-block-ethylene glycol polymer (PALE) by adjusting the chain length and the cross-linked segments structure. The groups (-OH, -C-O-C-, -C=O, and -C≡N) on the polymer chain induce the migration of lithium ions along the polymer chain.…”

“…Reproduced from Ref [123]. with permission from Elsevier; (i) the deposition mechanism of Li + ions and a schematic diagram of the Li anode surface in batteries assembled with LE, PAL, and PALE-3-6 GPEs[124]. Reproduced from Ref [124].…”