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Organic electrode materials (OEMs) have gathered extensive attention for aqueous zinc-ion batteries (AZIBs) due to their structural diversity and molecular designability. However, the reported research mainly focuses on the design of the planar configuration of OEMs and does not take into account the important influence of the spatial structure on the electrochemical properties, which seriously hamper the further performance liberation of OEMs. Herein, this work has designed a series of thioether-linked naphthoquinone-derived isomers with tunable spatial structures and applied them as the cathodes in AZIBs. The incomplete conjugated structure of the elaborately engineered isomers can guarantee the independence of the redox reaction of active groups, which contributes to the full utilization of active sites and high redox reversibility. In addition, the position isomerization of naphthoquinones on the benzene rings changes the zincophilic activity and redox kinetics of the isomers, signifying the importance of spatial structure on the electrochemical performance. As a result, the 2,2'-(1,4-phenylenedithio) bis(1,4-naphthoquinone) (p-PNQ) with the smallest steric hindrance and the most independent redox of active sites exhibits a high specific capacity (279 mAh g -1 ), an outstanding rate capability (167 mAh g -1 at 100 A g -1 ), and a long-term cycling lifetime (over 2800 h at 0.05 A g -1 )., (© 2024 Wiley‐VCH GmbH.)

The slow reaction kinetics and structural instability of organic electrode materials limit the further performance improvement of aqueous zinc-organic batteries. Herein, we have synthesized a Z-folded hydroxyl polymer polytetrafluorohydroquinone (PTFHQ) with inert hydroxyl groups that could be partially oxidized to the active carbonyl groups through the in situ activation process and then undertake the storage/release of Zn 2+ . In the activated PTFHQ, the hydroxyl groups and S atoms enlarge the electronegativity region near the electrochemically active carbonyl groups, enhancing their electrochemical activity. Simultaneously, the residual hydroxyl groups could act as hydrophilic groups to enhance the electrolyte wettability while ensuring the stability of the polymer chain in the electrolyte. Also, the Z-folded structure of PTFHQ plays an important role in reversible binding with Zn 2+ and fast ion diffusion. All these benefits make the activated PTFHQ exhibit a high specific capacity of 215 mAh g -1 at 0.1 A g -1 , over 3400 stable cycles with a capacity retention of 92 %, and an outstanding rate capability of 196 mAh g -1 at 20 A g -1 ., (© 2023 Wiley-VCH GmbH.)

Organic materials have attracted much attention in aqueous zinc-ion batteries (AZIBs) due to their sustainability and structure-designable, but their further development is hindered by the high solubility, poor conductivity, and low utilization of active groups, resulting in poor cycling stability, terrible rate capability, and low capacity. In order to solve these three major obstacles, a novel organic host, benzo[b]naphtho[2',3':5,6][1,4]dithiino[2,3-i]thianthrene-5,7,9,14,16,18-hexone (BNDTH), with abundant electroactive groups and stable extended π-conjugated structure is synthesized and composited with reduced graphene oxide (RGO) through a solvent exchange composition method to act as the cathode material for AZIBs. The well-designed BNDTH/RGO composite exhibits a high capacity of 296 mAh g -1 (nearly a full utilization of the active groups), superior rate capability of 120 mAh g -1 , and a long lifetime of 58 000 cycles with a capacity retention of 65% at 10 A g -1 . Such excellent performance can be attributed to the ingenious structural design of the active molecule, as well as the unique solvent exchange composition strategy that enables effective dispersion of excess charge on the active molecule during discharge/charge process. This work provides important insights for the rational design of organic cathode materials and has significant guidance for realizing ideal high performance in AZIBs., (© 2023 Wiley-VCH GmbH.)

Developing flexible electrodes with high active materials loading and excellent mechanical stability is of importance to flexible electronics, yet remains challenging. Herein, robust flexible electrodes with an encapsulated core-multishell structure are developed via a spraying-hydrothermal process. The multilayer electrode possesses an architecture of substrate/reduced graphene oxide (rGO)/bimetallic complex/rGO/bimetallic complex/rGO from the inside to the outside, where the cellulosic fibers serve as the substrate, namely, the core; and the multiple layers of rGO and bimetallic complex, are used as active materials, namely, the shells. The inner two rGO interlayers function as the cement that chemically bind to two adjacent layers, while the two outer rGO layers encapsulate the inside structure effectively protecting the electrode from materials detachment or electrolyte corrosion. The electrodes with a unique core-multishell structure exhibit excellent cycle stability and exceptional temperature tolerance (-25 to 40 °C) for lithium and sodium storage. A combination of experimental and theoretical investigations are carried out to gain insights into the synergetic effects of cobalt-molybdenum-sulfide (CMS) materials (the bimetallic complex), which will provide guidance for future exploration of bimetallic sulfides. This strategy is further demonstrated in other substrates, showing general applicability and great potential in the development of flexible energy storage devices., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)