Mxene-Derived Titanic Acid with an Ultralow-Potential as a Promising Anode for Aqueous Zinc-Ion Batteries

Replacing Zn metal with intercalated materials as the aqueous zinc-ion batteries (AZIBs) anode is an ef-fective strategy to solve serious zinc dendrites problem. MXene-based derived materials combine the ad-vantages of both derivatives with excellent electrochemical activity and MXene with high electrical conductivity. Here, we report an in situ derived strategy for synthesizing H2Ti3O7-MXene from common Ti3C2 MXene by one-step hydrothermal process with simultaneous alkalization and oxidation, followed by ion-exchange reaction. It is experimentally verified that H2Ti3O7 -MXene exhibits an extremely low char-ging voltage of only 0.25 V, which has a satisfactory potential for AZIBs anodes. Through characterization analyses, H2Ti3O7-MXene nanoflowers consist of countless connectively interlaced and entangled nanor-ibbons, which shorten the ion diffusion path and accelerate Zn2+ diffusion kinetics. The synergistic effect between H2Ti3O7 and MXene enables H2Ti3O7-MXene to achieve efficient and reversible Zn2+ (de)inter-calation. Specifically, at 0.10 A g-1, the specific capacity of 61.20 mAh g-1 is achieved and no significant discharge specific capacity decline occurs at 0.60-2.00 A g-1. The assembled zinc ion full-cell (ZnxMnO2// H2Ti3O7-MXene) shows the excellent cyclic stability and good coulombic efficiency during 600 GCD cycles. This work proves the feasibility of MXene-based derivatives for AZIBs anode and sheds light on developing efficient intercalated MXene derived anodes.(c) 2023 Elsevier B.V. All rights reserved.