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The aqueous zinc‐iodine battery is a promising energy storage device, but the conventional two‐electron reaction potential and energy density of the iodine cathode are far from meeting practical application requirements. Given that iodine is rich in redox reactions, activating the high‐valence iodine cathode reaction has become a promising research direction for developing high‐voltage zinc‐iodine batteries. In this work, by designing a multifunctional electrolyte additive trimethylamine hydrochloride (TAH), a stable high‐valence iodine cathode in four‐electron‐transfer I−/I2/I+ reactions with a high theoretical specific capacity is achieved through a unique amine group, Cl bidentate coordination structure of (TA)ICl. Characterization techniques such as synchrotron radiation, in situ Raman spectra, and DFT calculations are used to verify the mechanism of the stable bidentate structure. This electrolyte additive stabilizes the zinc anode by promoting the desolvation process and shielding mechanism, enabling the zinc anode to cycle steadily at a maximum areal capacity of 57 mAh cm−2 with 97 % zinc utilization rate. Finally, the four‐electron‐transfer aqueous Zn−I2 full cell achieves 5000 stable cycles at an N/P ratio of 2.5. The unique bidentate coordination structure contributes to the further development of high‐valence and high capacity aqueous zinc‐iodine batteries. [ABSTRACT FROM AUTHOR]

Rechargeable Li−Cl2 battery is a promising high energy density battery system. However, reasonable cycle life could only be achieved under low specific capacities due to the sluggish oxidation of LiCl to Cl2. Herein, we propose an amine‐functionalized covalent organic framework (COF) with catalytic activity, namely COF−NH2, that significantly decreases the oxidation barrier of LiCl and accelerates the oxidation kinetics of LiCl in Li−Cl2 cell. The resulting Li−Cl2 cell using COF−NH2 (Li−Cl2@COF−NH2) simultaneously exhibits low overpotential, ultrahigh discharge capacity up to 3500 mAh/g and a promoted utilization ratio of deposited LiCl at the first cycle (UR−LiCl) of 81.4 %, which is one of the highest reported values to date. Furthermore, the Li−Cl2@COF−NH2 cell could be stably cycled for over 200 cycles when operating at a capacity of 2000 mAh/g at −20 °C with a Coulombic efficiency (CE) of ≈100 % and a discharge plateau of 3.5 V. Our superior Li−Cl2 batteries enabled by organocatalyst enlighten an arena towards high‐energy storage applications. [ABSTRACT FROM AUTHOR]

The electrochemical conversion of nitrate pollutants into value‐added ammonia is a feasible way to achieve artificial nitrogen cycle. However, the development of electrocatalytic nitrate‐to‐ammonia reduction reaction (NO3−RR) has been hampered by high overpotential and low Faradaic efficiency. Here we develop an iron single‐atom catalyst coordinated with nitrogen and phosphorus on hollow carbon polyhedron (denoted as Fe−N/P−C) as a NO3−RR electrocatalyst. Owing to the tuning effect of phosphorus atoms on breaking local charge symmetry of the single‐Fe‐atom catalyst, it facilitates the adsorption of nitrate ions and enrichment of some key reaction intermediates during the NO3−RR process. The Fe−N/P−C catalyst exhibits 90.3 % ammonia Faradaic efficiency with a yield rate of 17980 μg h−1 mgcat−1, greatly outperforming the reported Fe‐based catalysts. Furthermore, operando SR‐FTIR spectroscopy measurements reveal the reaction pathway based on key intermediates observed under different applied potentials and reaction durations. Density functional theory calculations demonstrate that the optimized free energy of NO3−RR intermediates is ascribed to the asymmetric atomic interface configuration, which achieves the optimal electron density distribution. This work demonstrates the critical role of atomic‐level precision modulation by heteroatom doping for the NO3−RR, providing an effective strategy for improving the catalytic performance of single atom catalysts in different electrochemical reactions. [ABSTRACT FROM AUTHOR]

Aqueous zinc‐ion batteries (AZBs) show promises for large‐scale energy storage. However, the zinc utilization rate (ZUR) is generally low due to side reactions in the aqueous electrolyte caused by the active water molecules. Here, we design a novel solvation structure in the electrolyte by introduction of sulfolane (SL). Theoretical calculations, molecular dynamics simulations and experimental tests show that SL remodels the primary solvation shell of Zn2+, which significantly reduces the side reactions of Zn anode and achieves high ZUR under large capacities. Specifically, the symmetric and asymmetric cells could achieve a maximum of ∼96 % ZUR at an areal capacity of 24 mAh cm−2. In a ZUR of ∼67 %, the developed Zn−V2O5 full cell can be stably cycled for 500 cycles with an energy density of 180 Wh kg−1 and Zn‐AC capacitor is stable for 5000 cycles. This electrolyte structural engineering strategy provides new insight into achieving high ZUR of Zn anodes for high performance AZBs. [ABSTRACT FROM AUTHOR]