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Sustainability is one of the hot topics of today's research, in particular when it comes to energy‐storage systems such as batteries. Redox‐active molecules implemented in organic batteries represent a promising alternative to lithium‐ion batteries, which partially rely on non‐sustainable heavy metal salts. As an alternative, we propose benzothiazole, ‐oxazole and ‐imidazole derivatives as redox‐active moieties for polymers in organic (radical) batteries. The target molecules were identified by a combination of theoretical and experimental approaches for the investigation of new organic active materials. Herein, we present the synthesis, electrochemical characterization and theoretical investigation of the proposed molecules, which can later be introduced into a polymer backbone and used in organic polymer batteries. [ABSTRACT FROM AUTHOR]

The hydrophilic poly(2,2,6,6‐tetramethylpiperdinyloxy‐4‐yl‐methacrylamide) (PTMAm) was utilized as redox target material in an aqueous organic redox targeting flow battery (RTFB). This polymer is processed into granules, which contain a conductive agent and an alginate binder. By this, a hydrophilic, yet water‐insoluble redox target can be obtained. The target was combined with the redox mediator molecule N,N,N‐trimethyl‐2‐oxo‐2‐[(2,2,6,6‐tetramethylpiperidin‐4‐yloxyl)amino]ethan‐1‐ammonium chloride (TEMPOAmide), that has been reported earlier as flow battery active material. This target/mediator combination has been characterized electrochemically and flow battery testing has been done. Furthermore, in‐operando characterization of the redox target via electrolyte state‐of‐charge (SOC) monitoring has been performed for the first time. The approach provides estimates for the redox target's SOC changes during cycling. In addition, a figure of merit – the "redox targetivity" – is proposed, which provides insights into the efficiency of the targeting reaction and supports the future optimization of materials, cell designs, and operational parameters for RTFBs. [ABSTRACT FROM AUTHOR]

Crosslinked hydrophilic poly(2,2,6,6‐tetramethylpiperidinyl‐N‐oxyl‐co‐[2‐(methacryloyloxy)‐ethyl]trimethyl ammonium chloride) [poly(TEMPO‐co‐METAC)] polymers with different monomer ratios are synthesized and characterized regarding a utilization as electrode material in organic batteries. These polymers can be synthesized rapidly utilizing commercial starting materials and reveal an increased hydrophilicity compared to the state‐of‐the‐art poly(2,2,6,6‐tetramethylpiperidinyl‐N‐oxyl‐4‐methacrylate) (PTMA). By increasing the hydrophilicity of the polymer, a preparation of cathode composites is enabled, which can be used for aqueous semi‐organic batteries. Detailed battery testing confirms that the additional METAC groups do not impair the battery behavior while enabling straight‐forward zinc‐TEMPO batteries. [ABSTRACT FROM AUTHOR]

A vast variety of oxidation procedures is known to obtain 2,2,6,6‐tetramethylpiperidinyl‐4‐oxyl (TEMPO) moieties from its piperidinyl precursor. However, up to now no comprehensive study has been performed concerning the performance and feasibility for lab‐scale synthesis. With the focus on the ease of synthesis, occurring impurities, the reaction yield and the degree of oxidation (DoO), this study represents a thorough investigation of different oxidation processes yielding N‐oxyl radicals in a one‐step procedure. The resulting materials were investigated by redox titration and electron spin resonance spectroscopy to determine the DoO, which is the determining parameter for the yield of this oxidation reaction. The most promising procedures have been transferred to a polymeric material to evaluate the feasibility of the catalysts for more complex substrates. [ABSTRACT FROM AUTHOR]

Aqueous Zinc-batteries comprising organic cathode materials represent interesting candidates for sustainable, safe, environmentally friendly, and highly flexible secondary energy storage system. Here, we demonstrate that such an oxygen-tolerant, semi-organic setup can conveniently be prepared in an all-aqueous process, including all steps from the initial polymerization to the coin cell assembly without the need of any intermediate purification steps, and still reach high energy densities of 2.55 mAh cm−2. The TEMPO-modified and crosslinked poly(methacrylamide) cathode facilitates an excellent compatibility to the aqueous electrolyte and an efficient accessibility of the redox-active species due to the increased polarity of the material compared to the common poly(TEMPO-methacrylate) (PTMA). The material exhibits excellent stability (capacity retention of >99% after 1000 cycles at 5C) with low self-discharge and features high rate capabilities. The casting process from the aqueous slurry further appeared to be suitable for the preparation of ultra-thick but still homogeneous binder-free electrodes and exhibit total device capacities of approximately 4.5 mAh in a 2032-type coin cell. Since the overall process avoids harsh conditions or harmful solvents, is scalable, and relies on straightforward processing steps, it represents a promising step towards cost-effective and efficient rechargeable Zinc-based semi-organic batteries with competing capacities if further optimized. [Display omitted] • New poly (TEMPO-methacrylamide) polymer synthesized. • Obtainable through all-aqueous one-pot process. • Enables aqueous semi-organic coin cells with zinc anodes. • Stable long-term cycling at 1.5 V battery voltage. • High-capacity coin cells from ultra-thick electrodes. [ABSTRACT FROM AUTHOR]

Keywords: aqueous electrolyte; hydrophilic polymer; semi-organic battery; TEMPO; zinc battery EN aqueous electrolyte hydrophilic polymer semi-organic battery TEMPO zinc battery 1 1 1 09/22/22 20220920 NES 220920 B The Cover Feature b shows a schematic coin cell battery that is constructed from a metallic zinc anode, an electrolyte-soaked separator, and an organic polymer composite cathode. This electrolyte is represented by the Erlenmeyer flask in the right half of the image that features representative zinc perchlorate ions in aqueous solutions. Aqueous electrolyte, hydrophilic polymer, semi-organic battery, TEMPO, zinc battery. [Extracted from the article]

• The history of redox polymers can be dated back to 1944. • Organic active scaffold enables tailoring of battery properties. • Polymers for energy storage do not need to be highly defined. • Polymer solubility is a key factor for battery performance. • Many redox polymers could be used in more than a single specialized battery system. Renewable organic batteries represent a valuable option to store sustainably generated energy and can play a major role in phasing out current carbon-based energy production. Several approaches have emerged over the last 80 years that utilize organic redox materials as active components in batteries. In particular, polymers have gained considerable interest among numerous research groups due to their (1) fast redox chemistry, in comparison to conventional active materials, (2) straight-forward syntheses, and (3) tunable solubility, which represent favored properties for diverse electronic devices. Notably, the beginning of redox-active polymers is linked to the discovery of conductive polymers by Heeger, MacDiarmid and Shirakawa in 1977. Nevertheless, redox-active polymers were studied in 1944 making them a familiar class under the broader polymeric framework, which celebrate its 100th birthday in 2020, based on the pioneering publication by Staudinger in 1920. Since their beginning, redox-active polymers have evolved from an interesting phenomenon into a family of promising, tailor-made, battery materials that also made their way to commercialization. In this regard, this review focusses on the design of interesting polymeric, redox-active materials. Polymerization techniques are discussed regarding novel polymer architectures and utilitarian properties. The polymer architectures are subsequently analyzed within the application scenarios of solid-state batteries, pseudo-capacitors, and redox-flow batteries. Redox moieties are compared and an overview of diverse synthetic aspects as well as battery concepts for the optimal assembly of polymeric battery materials are given. [Display omitted] [ABSTRACT FROM AUTHOR]

A triol-functionalized 2,2′-bipyridine (bpy) derivative has been synthesized and used for the tris-alkoxylation of polyoxometalate (POM) precursors. The resultant POM-bpy conjugates of the Wells–Dawson- and Anderson-type feature a C–C bond as a linkage between the POM and bpy fragments. This structural motif is expected to increase the hydrolytic stability of the compounds. This is of particular relevance with respect to the application of POM-bpy metal complexes, as photocatalysts, in the hydrogen-evolution reaction (HER) in an aqueous environment. Accordingly, Rh(III) and Ir(III) complexes of the POM-bpy ligands have been prepared and characterized. These catalyst-photosensitizer dyads have been analyzed with respect to their electrochemical and photophysical properties. Cyclic and square-wave voltammetry, as well as UV/vis absorption and emission spectroscopy, indicated a negligible electronic interaction of the POM and metal-complex subunits in the ground state. However, emission–quenching experiments suggested an efficient intramolecular electron-transfer process from the photo-excited metal centers to the POM units to account for the non-emissive nature of the dyads (thus, suggesting a strong interaction of the subunits in the excited state). In-depth photophysical investigations, as well as a functional characterization, i.e., the applicability in the HER reaction, are currently ongoing. [ABSTRACT FROM AUTHOR]

Sustainability is one of the hot topics of today's research, in particular when it comes to energy-storage systems such as batteries. Redox-active molecules implemented in organic batteries represent a promising alternative to lithium-ion batteries, which partially rely on non-sustainable heavy metal salts. As an alternative, we propose benzothiazole, -oxazole and -imidazole derivatives as redox-active moieties for polymers in organic (radical) batteries. The target molecules were identified by a combination of theoretical and experimental approaches for the investigation of new organic active materials. Herein, we present the synthesis, electrochemical characterization and theoretical investigation of the proposed molecules, which can later be introduced into a polymer backbone and used in organic polymer batteries., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)