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Controlled radical copolymerizations present attractive avenues to obtain polymers with complicated compositions and sequences. In this work, we report the development of a visible‐light‐driven organocatalyzed controlled copolymerization of fluoroalkenes and acyclic N‐vinylamides for the first time. The approach enables the on‐demand synthesis of a broad scope of amide‐functionalized main‐chain fluoropolymers via novel fluorinated thiocarbamates, facilitating regulations over chemical compositions and alternating fractions by rationally selecting comonomer pairs and ratios. This method allows temporally controlled chain‐growth by external light, and maintains high chain‐end fidelity that promotes facile preparation of block sequences. Notably, the obtained F/N hybrid polymers, upon hydrolysis, afford free amino‐substituted fluoropolymers versatile for post modifications toward various functionalities (e.g. amide, sulfonamide, carbamide, thiocarbamide). We further demonstrate the in situ formation of polymer networks with desirable properties as protective layers on lithium metal anodes, presenting a promising avenue for advancing lithium metal batteries. [ABSTRACT FROM AUTHOR]

Controlling the structure and chemistry of solid electrolyte interphase (SEI) underpins the stability of electrolyte‐electrode interface, and is crucial for advancing rechargeable lithium metal batteries (LMBs). Here, we utilized photo‐controlled copolymerization to achieve the on‐demand synthesis of fluorosulfonyl fluoropolymers as unprecedented artificial SEI layers on Li metal anodes. This work not only enables instant formation of a hybrid polymer‐inorganic interphase that consists of a polymer‐enriched top layer and a LiF‐fortified bottom layer, originating from a single polymeric component, but also imparts various desirable physical properties (e.g. good mechanical strength and flexibility, high ion conductivity, low overpotential) to SEI via a single‐to‐divergent strategy. Model reactions and structural characterizations supported the formation of a divergent fluorinated interphase, which furnished prolonged stabilization of Li deposition, high coulombic efficiency and improved cycling behavior in electrochemical experiments. This work highlights the great potential of exploring reactive polymers as versatile coatings to stabilize Li metal anodes, providing a promising avenue to solve electrode‐electrolyte interfacial problems for LMBs. [ABSTRACT FROM AUTHOR]

Controlling the structure and chemistry of solid electrolyte interphase (SEI) underpins the stability of electrolyte-electrode interface, and is crucial for advancing rechargeable lithium metal batteries (LMBs). Here, we utilized photo-controlled copolymerization to achieve the on-demand synthesis of fluorosulfonyl fluoropolymers as unprecedented artificial SEI layers on Li metal anodes. This work not only enables instant formation of a hybrid polymer-inorganic interphase that consists of a polymer-enriched top layer and a LiF-fortified bottom layer, originating from a single polymeric component, but also imparts various desirable physical properties (e.g., good mechanical strength and flexibility, high ion conductivity, low overpotential) to SEI via a single-to-divergent strategy. Model reactions and structural characterizations supported the formation of a divergent fluorinated interphase, which furnished prolonged stabilization of Li deposition, high coulombic efficiency and improved cycling behavior in electrochemical experiments. This work highlights the great potential of exploring reactive polymers as versatile coatings to stabilize Li metal anodes, providing a promising avenue to solve electrode-electrolyte interfacial problems for LMBs., (© 2024 Wiley-VCH GmbH.)

The poor electrochemical stability window and low ionic conductivity in solid-state electrolytes hinder the development of safe, high-voltage, and energy-dense lithium metal batteries. Herein, taking advantage of the unique electronic effect of nitrile groups, we designed a novel azanide-based single-ion covalent organic framework (CN-iCOF) structure that possesses effective Li+ transport and high-voltage stability in lithium metal batteries. Density functional theory (DFT) calculations and molecular dynamics (MD) revealed that electron-withdrawing nitrile groups not only resulted in an ultralow HOMO energy orbital but also enhanced Li+ dissociation through charge delocalization, leading to a high tLi+ of 0.93 and remarkable oxidative stability up to 5.6 V (vs. Li+/Li) simultaneously. Moreover, cyanation leveraging Strecker reaction transformed reversible imine-linkage to a stable sp3-carbon-containing azanide anion, which facilitated contorted alignment of transport "ladders" along the one-dimensional anionic channels and the ionic conductivity could reach 1.33 × 10-5 S cm-1 at ambient temperature without any additives. As a result, CN-iCOF allowed operation of solid-state lithium metal batteries with high-voltage cathodes such as LiNi0.8Mn0.1Co0.1O2 (NCM811), demonstrating stable lithium deposition up to 1,100 h and reversible battery cycling at ambient temperature up to 4.5 V, shedding light on the importance of discovering new functionality for forthcoming high-performance batteries., (© 2024 Wiley‐VCH GmbH.)

Dendrite growth on electrode-electrolyte interphase has severely limited applications of lithium metal batteries (LMBs). Here, we developed an ionic alternating polymer with fluorocarbons and phosphonium cations in repeating units to regulate Li deposition for the first time. The combined functionalities in the F/P hybrid polymer exhibit remarkable characteristics as a protective layer on top of Li anode, demonstrating outstanding electrochemical stability, ion flux redistributing capability and adaptive chain mobility. Based on characterizations and simulations, this cationic interlayer could effectively furnish long-standing electrostatic shielding for anodes, allowing restrained coating decomposition and homogenized electric field distribution to induce dendrite-free Li deposition, and enabling full cells with enhanced rate and long-term cycling performance. Given the importance of LMBs, this work will promote polymer design to stabilize anodes with superior electrochemical behavior., (© 2023 Wiley-VCH GmbH.)

Ultra-high-molecular-weight (UHMW) polymers display outstanding properties and hold potential for wide applications. However, their precise synthesis remains challenging. Herein, we developed a novel reversible-deactivation radical polymerization based on the strong and selective fluorine-fluorine interaction, allowing chain-transfer agents to spontaneously differentiate into two groups that take charge of the chain growth and reversible deactivation of the growing chains, respectively. This method enables dramatically improved livingness of propagation, providing UHMW polymers with a surprisingly narrow molecular weight distribution (Đ≈1.1) from a variety of fluorinated (meth)acrylates and acrylamide at quantitative conversions under visible-light irradiation. In situ chain-end extensions from UHMW polymers facilitated the synthesis of well-defined block copolymers, revealing the excellent chain-end fidelity achieved by this method., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)