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Two-dimensional/three-dimensional hierarchical self-supporting potassium ammonium vanadate@MXene hybrid films exhibit excellent electrochemical performance. [Display omitted] Currently, aqueous zinc ion batteries (AZIBs) have grown to be a good choice for large-scale energy storage systems due to their high theoretical specific capacity, low redox potential, low cost, and non-toxicity of the aqueous electrolyte. However, it is still challenging to obtain high specific capacity and stability suitable cathodes. Herein, hierarchical self-supporting potassium ammonium vanadate@MXene (KNVO@MXene) hybrid films were prepared by vacuum filtration method. Due to the three-dimensional nanoflower structure of KNVO with dual ions intercalation, high conductivity of two-dimensional Ti 3 C 2 T x MXene, and the hierarchical self-supporting structure, the AZIB based on the KNVO@MXene hybrid film cathode possessed superior specific capacity (481 mAh/g at 0.3 A/g) and cycling stability (retaining 125 mAh/g after 1000 cycles at a high current density of 10 A/g). In addition, the storage mechanism was revealed by various ex-situ characterizations. Hence, a new viewpoint for the preparation of AZIB self-supporting cathode materials is presented. [ABSTRACT FROM AUTHOR]

Hierarchical accordion-like manganese oxide@carbon hybrid with strong interaction heterointerface exhibits outstanding electrochemical performance. [Display omitted] Aqueous zinc ion batteries have attracted extensive concern as a promising candidate for large-scale energy storage because of their high theoretical specific capacity, low cost and inherent safety. However, the lacking of applicable cathode materials with outstanding electrochemical performance have severely hindered the further development of aqueous zinc ion batteries. Herein, we report a hierarchical accordion-like manganese oxide@carbon (MnO@C) hybrid with strong interaction heterointerface and comprehensively inquire into its electrochemical performance as cathode materials for aqueous zinc ion batteries. The unique hierarchical accordion-like layered structure coupling with strong interaction heterointerface between small MnO and carbon matrix efficaciously improve the ion/electron transfer process and enhance structure stability of the MnO@C hybrid. Benefitting from these unique advantages, the MnO@C hybrid bestows excellent specific capacity of 456 mAh g−1 at 50 mA g−1. Impressively, the MnO@C hybrid presents distinguished long-term cycling stability with fairly low decay rates of only 0.0079 % per cycle even over 2000 cycles at 2000 mA g−1. Moreover, comprehensive characterizations are executed to elucidate the mechanism involved. Therefore, this work affords a new idea for developing outstanding performance manganese-based cathode materials for aqueous zinc ion batteries. [ABSTRACT FROM AUTHOR]

The hierarchical 3D a-V 2 O 5 @Ti 3 C 2 T x microsphere with impressive Zn2+ storage ability is prepared by a simple spray drying method. [Display omitted] • The hierarchical 3D a-V 2 O 5 @Ti 3 C 2 T x microsphere was prepared by a simple spray drying method. • The amorphous V 2 O 5 endows abundant active sites for Zn2+ storage and alleviates Ti 3 C 2 T x MXene nanosheets restacking. • The presence of outstanding conductivity MXene framework enhances the conductivity and reaction kinetics. • The 3D a-V 2 O 5 @Ti 3 C 2 T x exhibits ultrahigh reversible capacity, superior rate performance and splendid cycling stability. As candidates of the next generation batteries, aqueous zinc-ion batteries (ZIBs) have drawn widespread attention owing to the advantages of environmental friendliness, low cost and ultrahigh theoretical capacity. In order to obtain superior zinc ions (Zn2+) storage ability, the cathode materials with eminent electrochemical property are placed great expectations. Herein, the hierarchical 3D a-V 2 O 5 @Ti 3 C 2 T x microsphere is prepared by a simple spray drying process. In the heterostructure, the amorphous V 2 O 5 not only endows abundant active sites for Zn2+ storage but also effectively alleviates Ti 3 C 2 T x MXene nanosheets restacking. Meanwhile, the presence of conductive Ti 3 C 2 T x MXene framework significantly enhances the conductivity and reaction kinetics of the electrode material. As a result, the 3D a-V 2 O 5 @Ti 3 C 2 T x exhibits an impressive Zn2+ storage ability, including the high reversible capacity (604 mAh g−1 at 0.5 A g−1), the superior rate performance and the splendid cycling stability. Furthermore, the relevant mechanism is illustrated via various characterizations. Moreover, the as-fabricated pouch ZIBs based on the 3D a-V 2 O 5 @Ti 3 C 2 T x displays a potential practical application prospect as flexible energy storage devices. Hence, this work may provide an inspiration for the rational design of high performance ZIBs cathode materials. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous zinc-ion batteries are emerged as fascinating "beyond Li-ion" battery technologies for large-scale energy storage due to low cost, high theoretical capacity, high safety and environmental friendliness. However, developing cathode materials with outstanding electrochemical performance are prerequisites. Herein, the a-V 2 O 5 @Ti 3 C 2 T x heterostructure is prepared by in situ incorporating amorphous V 2 O 5 with Ti 3 C 2 T x MXene to enhance the rechargeable aqueous Zn-ion batteries performance. Benefitting from the distinctive amorphous structure of a-V 2 O 5 , outstanding conductivity of Ti 3 C 2 T x MXene and the strong synergistic effect between two components, the a-V 2 O 5 @Ti 3 C 2 T x heterostructure presents isotropic ion diffusion paths, plentiful ion storage sites and splendid conductivity. As a consequence, the a-V 2 O 5 @Ti 3 C 2 T x heterostructure displays excellent specific capacity of 544 mAh g−1 at 0.5 A g−1 and outstanding rate performance. Particularly, even at a fairly high current density of 30 A g−1, the a-V 2 O 5 @Ti 3 C 2 T x heterostructure shows an impressive specific capacity of 135 mAh g−1 along with about 100% coulombic efficiency after 1000 cycles. Furthermore, the mechanism related is expounded via comprehensive characterizations. Therefore, this work offers a way for developing high-performance vanadium-based cathode materials for aqueous zinc-ion batteries. [Display omitted] • Amorphous V 2 O 5 @Ti 3 C 2 T x was fabricated via a simple in situ synthetic method. • Synergistic effect amorphous V 2 O 5 and Ti 3 C 2 T x endows fascinating properties. • The cathode presents outstanding specific capacity and cycling stability. • The mechanisms involved were elucidated via comprehensive characterizations. [ABSTRACT FROM AUTHOR]