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 effective strategy to solve serious zinc dendrites problem. MXene-based derived materials combine the advantages of both derivatives with excellent electrochemical activity and MXene with high electrical conductivity . Here, we report an in situ derived strategy for synthesizing H 2 Ti 3 O 7 −MXene from common Ti 3 C 2 MXene by one-step hydrothermal process with simultaneous alkalization and oxidation , followed by ion-exchange reaction. It is experimentally verified that H 2 Ti 3 O 7 −MXene exhibits an extremely low charging voltage of only 0.25 V, which has a satisfactory potential for AZIBs anodes. Through characterization analyses, H 2 Ti 3 O 7 −MXene nanoflowers consist of countless connectively interlaced and entangled nanoribbons , which shorten the ion diffusion path and accelerate Zn 2+ diffusion kinetics. The synergistic effect between H 2 Ti 3 O 7 and MXene enables H 2 Ti 3 O 7 −MXene to achieve efficient and reversible Zn 2+ (de)intercalation. 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 (Zn x MnO 2 //H 2 Ti 3 O 7 −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.