Aqueous zinc-ion batteries (ZIBs) are promising for next-generation energy storage. However, the reported electrode materials for ZIBs are facing shortcomings including low capacity and unsatisfactory cycling stability etc. Herein, hexaazatrinaphthalenequione (HATNQ) is reported for aqueous ZIBs. The HATNQ electrodes delivered an ultrahigh capacity (482.5 mAh g À 1 at 0.2 A g À 1 ) and outstanding cyclability of > 10 000 cycles at 5 A g À 1 . The capacity sets a new record for organic cathodes in aqueous ZIBs. The high performances are ascribed to the rich C=O and C=N groups that endowed HATNQ with a 2D layered supramolecular structure by multiple hydrogen bonds in plane with π-π interactions out-of-plane, leading to enhanced charge transfer, insolubility, and rapid ion transport for fast-charge and -discharge batteries. Moreover, the 2D supramolecular structure boosted the storage of Zn 2 + /H + , particularly the storage of Zn 2 + , due to the more favorable O•••Zn•••N coordination in HATNQ.

MXenes, or transition metal carbides or nitrides, as an advanced 2D materials have already attracted extensive attention due to their high conductivity and large specific surface area for applications in the field of energy storage. MXenes also have many other advanced properties such as good transmittance and adjustable work function over a large range. However, few works study the properties of MXenes in the field of optoelectronics. Here, the optoelectronic properties of Ti3C2TX (with a work function of 4.37 eV) on n‐type silicon (n‐Si) of vertical van der Waals heterostructures are studied. The Ti3C2TX not only functions as the transparent electrode but also contributes to the separation and transport of photo‐induced carriers. After investigations on the influence of annealing, temperature, illumination, and applied voltage on the performance of Ti3C2TX/n‐Si Schottky junction heterostructures, this study fabricates a self‐driven vertical junction photodetectors with high response and recovery speeds. It is believed that the excellent photoelectric properties of MXenes will attract many researchers' attention to the application of MXenes in the photoelectrical field.

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