Synergetic Effect of Alkali‐Site Substitution and Oxygen Vacancy Boosting Vanadate Cathode for Super‐Stable Potassium and Zinc Storage

Abstract

Layer‐structured metal vanadates have attracted extensive attention as cathode materials due to multi‐electron redox reactions and versatile cations storage capability. Nevertheless, their actual promotion is still hindered by the sluggish reaction kinetics and inferior phase transition upon repeated cations (de)intercalation. Here, large‐sized NH4+ is introduced into the K‐site of K0.43(NH4)0.12V2O5–δ to enable more kinetically favorable oxygen vacancies. The reinforced structure ensures complete solid‐solution phase transition and buffers the dramatic structural change upon potassium storage. The stable presence of NH4+ as pillars during cycling is also confirmed. Meanwhile, the oxygen vacancies induced by alkali‐site substitution can facilitate ion diffusion and enhance the electronic conductivity, as further demonstrated by theoretical calculations. Therefore, it exhibits a high capacity of 117.8 mA g−1 at 20 mA g−1 with smooth profiles and superior capacity retention of 92.5% after 800 cycles at 1000 mA g−1. Such an effective synergetic strategy also promotes its zinc storage capability, which performs negligible self‐discharge behavior and retains a reversible capacity of 216.8 mAh g−1 after 3000 cycles at 10 A g−1. This synergetic strategy may provide novel perspectives to develop layer‐structured cathode and facilitate its practical application in energy storage devices.

A hydrated deep eutectic electrolyte with finely-tuned solvation chemistry for high-performance zinc-ion batteries

“…The peaks at 760 cm −1 and 1031 cm −1 are derived from the stretching mode of the VO bond. 56,57 These peaks, especially those located at 760 cm −1 and 1031 cm −1 , gradually weakened during the discharge process and then slightly strengthened during the charge process, which was due to the intercalation/deintercalation of Zn 2+ (Fig. 6h and i).…”

Opportunities for biocompatible and safe zinc-based batteries

“…46 Vanadium-based materials provide a high capacity and good rate performance, but their lower reaction potential (usually 0.4–1.4 V) greatly limits the energy density. 47 Additionally, both manganese-based and vanadium-based materials suffer from cathode dissolution, while the zinc anode issues in mildly acidic electrolytes also lead to cell degradation. Thus, much attention has been focused on the optimization strategies, like pre-intercalation and element doping for the cathode materials, surface coating and structural design for the anode.…”

Oxygen Vacancies ZnO1–x as Anode Materials for Superior-Performance Zinc-Nickel Alkaline Batteries

“…Consequently, introducing oxygen vacancies into the material is considered as an effective strategy to increase the electronic conductivity. 27,28 In this work, we have reasonably prepared ZnO containing oxygen vacancies through a simple reduction annealing strategy, which can be used as an anode material for Zn-Ni alkaline batteries. The key to this idea is to utilize the oxygen vacancies in the ZnO by providing more active sites during charging and discharging, which accelerates charge/ion transfer and thus shows excellent electrochemical performance during battery cycles.…”