Tailoring Ultrahigh Energy Density and Stable Dendrite-Free Flexible Anode with Ti3C2Tx MXene Nanosheets and Hydrated Ammonium Vanadate Nanobelts for Aqueous Rocking-Chair Zinc Ion Batteries

Exploiting Zn metal-free anode materials would be an effective strategy to resolve the problems of Zn metal dendrites that severely hinder the development of Zn ion batteries (ZIBs). However, the study of Zn metal-free anode materials is still in their infancy, and more importantly, the low energy density severely limits their practical implementations. Herein, a novel (NH4)(2)V10O25 center dot 8H(2)O@Ti3C2Tx (NHVO@Ti3C2Tx) film anode is proposed and investigated for constructing rocking-chair ZIBs. The NHVO@Ti3C2Tx electrode shows a capacity of 514.7 mAh g(-1) and presents low potential which is 0.59 V (vs Zn2+/Zn) at 0.1 A g(-1). The introduction of Ti3C2Tx not only affords an interconnected conductive network, but also stabilizes the NHVO nanobelts structure for a long cycle life (84.2% retention at 5.0 A g(-1) over 6000 cycles). As a proof-of-concept, a zinc metal-free full battery is successfully demonstrated, which delivers the highest capacity of 131.7 mAh g(-1) (mass containing anodic and cathodic) and energy density of 97.1 Wh kg(-1) compared to all reported aqueous rocking-chair ZIBs. Furthermore, a long cycling span of 6000 cycles is obtained with capacity retention reaching up to 92.1%, which is impressive. This work is expected to provide new moment toward V-based materials for rocking-chair ZIBs.

Automated summary

This study explores a novel NHVO@Ti3C2Tx film anode for rocking-chair ZIBs, which exhibits high capacity, low potential, and long cycling life. A zinc metal-free full battery is successfully demonstrated with impressive cycling span and energy density, indicating a significant step towards V-based materials for rocking-chair ZIBs.