Potassium Ammonium Vanadate with Rich Oxygen Vacancies for Fast and Highly Stable Zn-Ion Storage

Abstract

Vanadium-based materials have been extensively studied as promising cathode materials for zinc-ion batteries because of their multiple valences and adjustable ion-diffusion channels. However, the sluggish kinetics of Zn-ion intercalation and less stable layered structure remain bottlenecks that limit their further development. The present work introduces potassium ions to partially substitute ammonium ions in ammonium vanadate, leading to a subtle shrinkage of lattice distance and the increased oxygen vacancies. The resulting potassium ammonium vanadate exhibits a high discharge capacity (464 mAh g–1 at 0.1 A g–1) and excellent cycling stability (90% retention over 3000 cycles at 5 A g–1). The excellent electrochemical properties and battery performances are attributed to the rich oxygen vacancies. The introduction of K+ to partially replace NH4 + appears to alleviate the irreversible deammoniation to prevent structural collapse during ion insertion/extraction. Density functional theory calculations show that potassium ammonium vanadate has a modulated electron structure and a better zinc-ion diffusion path with a lower migration barrier.

A cerium vanadate/S heterostructure for a long-life zinc-ion battery: efficient electron transfer by the anchored sulfur

“…1j, a strong signal is detected at around 3443 G for CeVS, which corresponds to the effective gyromagnetic ratio at an isotropic g of 1.96 and provides evidence for the oxygen vacancies. 27,28…”

“…1j, a strong signal is detected at around 3443 G for CeVS, which corresponds to the effective gyromagnetic ratio at an isotropic g of 1.96 and provides evidence for the oxygen vacancies. 27,28 In order to further determine the compositions in CeVO and CeVS, thermogravimetric (TG) curves were recorded from room temperature to 800 °C under a N 2 atmosphere. For comparison, the TG curves of V 2 O 5 and VS 2 were recorded under the same conditions.…”

Pseudocapacitive Vanadium Nitride Quantum Dots Modified One-Dimensional Carbon Cages Enable Highly Kinetics-Compatible Sodium Ion Capacitors

“…Intrinsic pseudocapacitance can emerge when the material with redox metal centers contribute to the pseudocapacitance near the surface or the material with a crystalline network provides spacious ion transport pathways . Extrinsic pseudocapacitance originates when the material not only is engineered at the nanoscale but also possesses a heteroatom-doped porous conductive network so that they can provide abundant Na + storage sites on the surface or near-surface region. − In these regards, improving the whole pseudocapacitance contribution by considering both intrinsic and extrinsic pseudocapacitances to select pseudocapacitive material with superior structural design for boosting fast surface Na + storage is urgently desired.…”

Boosting the Stability of Oxygen Vacancies in α‐Co(OH)2 Nanosheets with Coordination Polyhedrons as Rivets for High‐Performance Alkaline Hydrogen Evolution Electrocatalyst

“…[23] The incorporation of oxygen vacancies can not only modulate the electronic structure of materials but also participate in the construction of catalytic active sites, which makes oxygen vacancy engineering widely used in various fields such as photocatalysis, [24,25] electrocatalysis, [26,27] and energy storage. [28] For instance, the introduction of extrinsic oxygen vacancies can strengthen the metal-support interaction, enhancing the stability of the structure of catalysts as well as the tolerance of catalysts to oxygenates. [29] Additionally, a large number of oxygen vacancies can form dense dislocation layers to hinder the intragranular cracks and phase transformation, improving the structural and cycling stability of the Ni-rich cathode.…”