In-situ electrochemical etching of V4AlC3 MAX to V2O5/C composite as Zn-ion storage host

Although V2O5 is considered as promising cathode for aqueous Zn-ion batteries (AZIBs), the poor intrinsic conductivity and unstable structure can significantly hamper its electrochemical energy storage capability. In this work, an in-situ formation strategy of V2O5/C composite nanosheets-derived from V4AlC3 MAX is reported, as an efficient Zn2+ storage host via electrochemically etching-induced phase transition strategy. And the mechanism behind the V4AlC3 MAX electrode conversion were systematically studied. The results revealed that the V-Al bond and Al 1s peak of V4AlC3 were gradually disappearing at prolonged cycling, meanwhile the high valence state vanadium was formed simultaneously as the V2O5/C composite. Benefiting from the efficient re-action kinetics endowed by the V2O5/C nanosheets, such V(4)AlC(3 )MAX derived electrode can deliver a high specific capacity of 10(2 )mA h g(-1) (20 A/g) at the cut-off voltage of 2.0 V, Furthermore, discharge capacity of 158 mA h g(- 1 )after 3000 cycles at 10 A/g can be retained, confirming it a superior rate capability and cycling sta-bility. The work demonstrates an effective strategy for green and advanced cathode material design and high-performance AZIBs.

Automated summary

This work presents an in-situ formation strategy of V2O5/C composite nanosheets derived from V4AlC3 MAX, as an efficient Zn2+ storage host, through electrochemically etching-induced phase transition. The V4AlC3 MAX electrode conversion mechanism is studied systematically. The results demonstrate that the derived electrode exhibits high specific capacity, superior rate capability, and cycling stability, providing an effective strategy for green and advanced cathode material design.