Engineering porous structure in Bi-component-active ZnO quantum dots anchored vanadium nitride boosts reaction kinetics for zinc storage

Abstract

The electrochemical performance of aqueous zinc-ion battery (AZIB) is largely dependent on the fast reaction kinetics, therefore, researchers made a lot of research to improve the ion/electron transfer rate, but did not achieve satisfactory results. Herein, pore engineering is performed by a simple self-sacrificial strategy to obtain bi-component-active ZnO quantum dots (QDs) modified VN nanosheets (ZnO-QDs-VN-0.5) with an interconnected framework. The abundant and evenly distributed porous structure provides a short Zn 2+ ion channel for rapid diffusion. Compared to bulk VN-0.5, a unique high-surficial fast electrochemical reaction process is realized by rationally design the electrode. The formed ZnO-QDs-VN-0.5 exhibits a satisfactory specific capacity (384.1 mAh g −1 at 0.1 A g −1 ), good rate capability and satisfactory cycle life. Moreover, the flexible quasi-solid-state ZnO-QDs-VN-0.5//Zn battery also shows excellent stability, high energy density and power density, which proves that this material can be applied in different fields. The excellent performance may be due to the reasonable adjustment of the multi-phase interface and porous structure control, which significantly promotes the transfer rate of ions of ZnO-QDs-VN-0.5 (D Zn 2+ ≈10 −8 cm 2 s −1 ), and greatly enhances the ion storage sit. In addition, the mechanism of the electrochemical reaction was elucidated by different ex-situ methods. This work provides great hope for the preparation of porous electrode materials and provides a basis for guiding the construction of electrode materials with excellent performance. • The ZnO-QDs-VN-0.5 is used as the cathode material of AZIBs for the first time. • The ZnO-QDs-VN-0.5 cathode deliver high capacity and excellent long cycle stability. • The flexible quasi-solid-state ZnO-QDs-VN-0.5//Zn battery also shows excellent stability. • The Zn-storage mechanism of ZnO-QDs-VN cathode was discussed.