Anodic Oxidation Strategy toward Structure-Optimized V₂O₃ Cathode via Electrolyte Regulation for Zn-Ion Storage

Abstract

The lack of suitable cathodes is one of the key reasons that impede the development of aqueous zinc-ion batteries. Because of the inherently unsuitable structure and inferior physicochemical properties, the low-valent V2O3 as Zn2+ host could not be effectively discharged. Herein, we demonstrate that V2O3 (theoretical capacity up to 715 mAh g–1) can be utilized as a high-performance cathode material by an in situ anodic oxidation strategy. Through simultaneously regulating the concentration of the electrolyte and the morphology of the V2O3 sample, the ultraefficient anodic oxidation process of the V2O3 cathode was achieved within the first charging, and the mechanism was also schematically investigated. As expected, the V2O3 cathode with a hierarchical microcuboid structure achieved a nearly two-electron transfer process, enabling a high discharging capacity of 625 mAh g–1 at 0.1 A g–1 (corresponding to a high energy density of 406 Wh kg–1) and cycling stability (100% capacity retention after 10 000 cycles). This work not only sheds light on the phase transition process of low-valent V2O3 but also exploits a method toward design of advanced cathode materials.

Adjusting the Valence State of Vanadium in VO2(B) by Extracting Oxygen Anions for High‐Performance Aqueous Zinc‐Ion Batteries

“…The multi‐sweep CV curves method is often used to analyze the kinetics of electrode reaction [20,21] . The role of oxygen vacancy in improving electrochemical performance was further proved with the utilization of abovementioned way in this work.…”

“…A typical fraction case at 1.0 mV s −1 is provided in Figure S7b. Compared to the cell‐type charge ion storage process, the ultra‐high capacitor‐type storage process has competitive advantage of faster charging and higher power density [20,21,24] . Therefore, it should be noted that increased capacitive charge‐storage capacity and rapid, highly reversible reaction kinetics can be achieved by reducing the concentration of oxygen anions, owing to the high surface reactivity [10] …”

A High‐Performance, Tailorable, Wearable, and Foldable Solid‐State Supercapacitor Enabled by Arranging Pseudocapacitive Groups and MXene Flakes on Textile Electrode Surface

“…Besides, the ratios of capacitive contribution at different scan rates were explored based on the following relationship: where k 1 v is the fraction of capacitive contribution and k 2 v 1/2 is the fraction of diffusion contribution. [ 46 ] It can be seen from Figure 5b,c, the capacitive contribution for the total current rises from 63% at 10 to 84% at 50 mV s −1 . The high capacitive contribution for the charge storage is due to on the one hand, high electron conductivity of carbon material, and titanium carbide, and on the other hand, small electrolyte ions (hydrion) able to be fast penetrating into surface‐active skin layer of MNCFT and ONCFT electrodes (Figure 5d).…”

Understanding the Design Principles of Advanced Aqueous Zinc‐Ion Battery Cathodes: From Transport Kinetics to Structural Engineering, and Future Perspectives

“…While for morphology control, the rational design of regular nanostructure is expected to endow the cathode materials with high specific surface area, rich active sites, short ion/ electron transport path, and fast reaction kinetics. [253,254] Therefore, morphology control also has been considered as an effective strategy for designing advanced AZIBs cathode materials. Normally, nanostructure can be classified into 0D, 1D, 2D, and 3D materials from the perspective of spatial growth.…”