Revealing the Self-Generated Heterointerface of NaV₂O₅ in Zn Storage via a Scalable Production Method

Solid-state sintering has been widely used as the most typical preparation method for nanomaterials. However, it usually requires high-pressure and high-temperature conditions because a slow solid-state diffusion kinetics and the presence of pores would impede proper ion diffusion. Herein, a simple and scalable method, so-called template-assisted solid-state sintering, has been utilized to synthesize a two-dimensional (2D) lamellar NaV2O5 as a cathode for aqueous zinc-ion batteries (AZIBs), and its mechanism of the improved preparation method is explored. A combined series of in situ/ex situ measurements and density functional theory (DFT) calculation reveal the Zn storage mechanism of the Zn//NaV2O5 system. A new phase of Zn3(OH)2V2O7(H2O)2 will be irreversibly generated, resulting in a self-generated heterointerface of Zn3(OH)2V2O7(H2O)2/NaV2O5. It will tune the electronic structure of NaV2O5 and accelerate the diffusion of Zn in the bulk phase, which inspires regulation of its generation for beneficial effects. In addition, a self-healing quasi-solid battery using the designed cathode has been assembled to demonstrate its application in the field of flexible wearables. This work offers a novel concept and path for creating the cathode materials for high-performance aqueous/nonaqueous batteries.