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1. Task-Specific Phosphonium Iongels by Fast UV-Photopolymerization for Solid-State Sodium Metal Batteries

   https://doi.org/10.3390/gels8110725  

   Porcarelli, Luca; Olmedo-Martínez, Jorge L.; Sutton, Preston; Bocharova, Vera; Fdz De Anastro, Asier; Galceran, Montserrat; Sokolov, Alexei P.; Howlett, Patrick C.; Forsyth, Maria; Mecerreyes, David (November 2022, Gels)

   Sodium metal batteries are an emerging technology that shows promise in terms of materials availability with respect to lithium batteries. Solid electrolytes are needed to tackle the safety issues related to sodium metal. In this work, a simple method to prepare a mechanically robust and efficient soft solid electrolyte for sodium batteries is demonstrated. A task-specific iongel electrolyte was prepared by combining in a simple process the excellent performance of sodium metal electrodes of an ionic liquid electrolyte and the mechanical properties of polymers. The iongel was synthesized by fast (<1 min) UV photopolymerization of poly(ethylene glycol) diacrylate (PEGDA) in the presence of a saturated 42%mol solution of sodium bis(fluorosulfonyl)imide (NaFSI) in trimethyl iso-butyl phosphonium bis(fluorosulfonyl)imide (P111i4FSI). The resulting soft solid electrolytes showed high ionic conductivity at room temperature (≥10−3 S cm−1) and tunable storage modulus (104–107 Pa). Iongel with the best ionic conductivity and good mechanical properties (Iongel10) showed excellent battery performance: Na/iongel/NaFePO4 full cells delivered a high specific capacity of 140 mAh g−1 at 0.1 C and 120 mAh g−1 at 1 C with good capacity retention after 30 cycles. 

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2. Structural, Ionic, and Electronic Properties of Solid-State Phthalimide-Containing Polymers for All-Organic Batteries

   Alessandri, R; Li, C_H; Keating, S; Mohanty, K; Peng, A; Lutkenhaus, J; Rowan, S; Tabor, D; de_Pablo, J (June 2024, JACS Au)

   Redox-active polymers serving as the active materials in solid-state electrodes offer a promising path toward realizing all-organic batteries. While both cathodic and anodic redox-active polymers are needed, the diversity of the available anodic materials is limited. Here, we predict solid-state structural, ionic, and electronic properties of anodic, phthalimide-containing polymers using a multiscale approach that combines atomistic molecular dynamics, electronic structure calculations, and machine learning surrogate models. Importantly, by combining information from each of these scales, we are able to bridge the gap between bottom-up molecular characteristics and macroscopic properties such as apparent diffusion coefficients of electron transport (Dapp). We investigate the impact of different polymer backbones and of two critical factors during battery operation: state of charge and polymer swelling. Our findings reveal that the state of charge significantly influences solid-state packing and the thermophysical properties of the polymers, which, in turn, affect ionic and electronic transport. A combination of molecular-level properties (such as the reorganization energy) and condensed-phase properties (such as effective electron hopping distances) determine the predicted ranking of electron transport capabilities of the polymers. We predict Dapp for the phthalimide-based polymers and for a reference nitroxide radical-based polymer, finding a 3 orders of magnitude increase in Dapp (≈10–6 cm2 s–1) with respect to the reference. This study underscores the promise of phthalimide-containing polymers as highly capable redox-active polymers for anodic materials in all-organic batteries, due to their exceptional predicted electron transport capabilities. 

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3. High‐Temperature and High‐Energy‐Density Dipolar Glass Polymers Based on Sulfonylated Poly(2,6‐dimethyl‐1,4‐phenylene oxide)

   https://doi.org/10.1002/anie.201710474  

   Zhang, Zhongbo; Wang, David H.; Litt, Morton H.; Tan, Loon‐Seng; Zhu, Lei (January 2018, Angewandte Chemie International Edition)

   Abstract A new class of high‐temperature dipolar polymers based on sulfonylated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SO₂‐PPO) was synthesized by post‐polymer functionalization. Owing to the efficient rotation of highly polar methylsulfonyl side groups below the glass transition temperature (T_g≈220 °C), the dipolar polarization of these SO₂‐PPOs was enhanced, and thus the dielectric constant was high. Consequently, the discharge energy density reached up to 22 J cm⁻³. Owing to its highT_g , the SO₂‐PPO₂₅sample also exhibited a low dielectric loss. For example, the dissipation factor (tan δ) was 0.003, and the discharge efficiency at 800 MV m⁻¹was 92 %. Therefore, these dipolar glass polymers are promising for high‐temperature, high‐energy‐density, and low‐loss electrical energy storage applications. 

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4. Novel Cu(Zn)–Ge–P compounds as advanced anode materials for Li-ion batteries

   https://doi.org/10.1039/d0ee03553j  

   Li, Wenwu; Shen, Pengfei; Yang, Lufeng; Chen, Anjie; Wang, Jeng-Han; Li, Yunyong; Chen, Hailong; Liu, Meilin (April 2021, Energy & Environmental Science)

   null (Ed.)

   Both electronic and ionic conductivities are of high importance to the performance of anode materials for Li-ion batteries. Many large capacity anode materials (such as Ge) do not have sufficiently high electronic and ionic conductivities required for high-rate cycling. Here, we report a novel ternary compound, copper germanium phosphide (CuGe 2 P 3 ), as a high-rate anode. Being synthesized via a facile and scalable mechanochemistry method, CuGe 2 P 3 has a cation-disordered sphalerite structure and offers higher ionic and electronic conductivities and better tolerance to volume change during cycling than Ge, as confirmed by first principles calculations and experimental characterization, including high-resolution synchrotron X-ray diffraction, HRTEM, SAED, XPS and Raman spectroscopy. Furthermore, the results suggest that CuGe 2 P 3 has a reversible Li-storage mechanism of conversion reaction. When composited with graphite by virtue of a two-stage ball-milling process, the yolk–shell structure of the amorphous carbon-coated CuGe 2 P 3 nanocomposite (CuGe 2 P 3 /C@Graphene) delivers a high initial coulombic efficiency (91%), a superior cycling stability (1312 mA h g −1 capacity after 600 cycles at 0.2 A g −1 and 876 mA h g −1 capacity after 1600 cycles at 2 A g −1 ), and an excellent rate capability (386 mA h g −1 capacity at 30 A g −1 ), surpassing most Ge-based anodes reported to date. Moreover, a series of cation-disordered new phases in the Cu(Zn)–Ge–P family with various cation ratios offer similar Li-storage properties, achieving high reversible capacities with high initial coulombic efficiencies and desirable redox chemistry with improved safety. 

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5. Selective Membrane for Non‐Aqueous Electrochemical Flow Cells

   https://doi.org/10.1002/adfm.202506275  

   Leroux, Charles_R; Geise, Geoffrey_M; Koenig_Jr, Gary_M (June 2025, Advanced Functional Materials)

   Abstract Non‐aqueous redox flow batteries can support the growing need for grid scale energy storage. Conductive and selective membranes are critical to enabling advanced flow battery technology with higher energy density and lower cost. Herein, a series of crosslinked poly(phenylene oxide)‐based membranes functionalized with phenoxyaniline tri‐sulfonate fixed charges are developed and reported. Increasing the degree of functionalization increased the theoretical ion exchange capacity (IEC) to 2.62 mEq g⁻¹compared with a previously achieved maximum of 2.06 mEq g⁻¹for these materials. Increasing membrane IEC increased conductivity (up to 0.41 mS cm⁻¹) and decreased permeability (<1 × 10⁻⁹cm²s⁻¹) based on ex situ measurements. While further improvements are still necessary for economically competitive non‐aqueous flow battery applications, these values are among the highest selectivity reported for cation exchange membranes in non‐aqueous electrolytes. In symmetric non‐aqueous electrochemical flow cell testing, current densities over 2 mA cm⁻²are achieved, although cell polarization is higher than expected. Long‐term cycling is performed at 1 mA cm⁻²with average coulombic efficiency over 99% maintained for over 70 cycles. This work reinforces that both ex situ transport properties and electrochemical cell evaluation are necessary when evaluating potential membrane materials, although reporting of both is presently uncommon in the literature. 

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