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• The few-layered MoS 2 nanosheets with different phase contents were prepared by an efficient controllable phase engineering. • The optimized material shows outstanding specific capacity and excellent long cycling performances. • The mechanisms involved were elucidated by systematical characterizations. • The DFT simulations reveal that the 1T phase MoS 2 has much lower Zn diffusion energy barriers. Recently, aqueous rechargeable Zn-ion batteries have attracted extensive attention, owing to their low-cost, high operational safety and environmental friendliness. However, the aqueous zinc-ion battery is still in a very infant stage, and the main challenge is to develop the ideal cathode due to the sluggish kinetics and low reversibility of divalent zinc ions. Herein, for the first time, we report controllable phase engineered few-layered MoS 2 nanosheet as cathode materials for rechargeable aqueous Zn-ion batteries and systematically study their performance. We found that the obtained MoS 2 with different phase contents showed distinct performance in the rechargeable aqueous zinc-ion battery. In particular, the MoS 2 nanosheets with ~70% 1T phase content displays excellent specific capacity and shows outstanding long-term cyclic stability. The mechanisms involved were clarified by not only comprehensive characterizations, but also the density functional theory (DFT) simulations that reveal the 1T phase MoS 2 has much lower Zn diffusion energy barriers. This study provides new insight into the effect of different phases on the performance of MoS 2 -based electrodes and will improve our understanding of developing better cathodes for the aqueous rechargeable Zn-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]