Ca/Ni Codoping Enables the Integration of High-Rate and High-Capacity Zn-Ion Storage Performances for Layered Hydrated Vanadate

Abstract

Layered hydrated vanadates have been regarded as promising cathode materials for Zn-ion batteries, while their electrochemical properties have been proved to be highly related to the species of the interlayer cations. However, because the single species of the interlayer cation can hardly endow the layered materials with comprehensively favorable properties, the introduction of multiple interlayer cations may offer an avenue to further optimization of the Zn-ion storage performance. Herein, this work introduces the codoping of Ca/Ni-ions in the structure of hydrated vanadate (Ca0.19Ni0.08V2O5·0.85H2O), which not only upgrades the specific capacities but also gives rise to high rate and cycling performances. Specifically, the interlayer Ni-ion in the structure plays a vital role in contributing to the high charge storage capability via participating in the electrochemical reactions. Meanwhile, the Ca-ion could stably act as pillars, pinning the adjacent VO x layers and thus leading to the structural stability of the layered material during operation. Moreover, the synergistic effects of the codoping result in the enlarged lattice spacing, which incurs the nearly zero-strain structural evolution processes with solid-solution-like charge storage behaviors. Accordingly, on the basis of a multiple-ion doping strategy, this study offers an effective approach to further boost the Zn-ion storage performance of hydrated vanadates.

Improved Reversible Zinc Storage Achieved in a Constitutionally Crystalline‐Stable Mn(VO3)2 Nanobelts Cathode

“…For the initial state, all the peaks belong to the characteristic peak of V 5+ with the binding energy of 517.4 eV and 524.8 eV corresponded with V 2p 3/2 and V 2p 1/2 respectively [40] . In the full discharging condition (0.2 V), the peak of V 2p 3/2 could be deconvoluted into three different peaks corresponding to weak V 3+ and V 5+ signal and dominant V 4+ specie [41] . The other V 2p 1/2 orbit can also be indexed to V 3+ , V 4+ and V 5+ , respectively [42] .…”

“…[40] In the full discharging condition (0.2 V), the peak of V 2p 3/2 could be deconvoluted into three Chemistry-A European Journal different peaks corresponding to weak V 3 + and V 5 + signal and dominant V 4 + specie. [41] The other V 2p 1/2 orbit can also be indexed to V 3 + , V 4 + and V 5 + , respectively. [42] The valence states change suggest V 5 + was reduced to V 4 + and V 3 + with the chemical intercalation of Zn 2 + .…”

Vanadium Oxide Cathode Coinserted by Ni2+ and NH4+ for High-Performance Aqueous Zinc-Ion Batteries

“…However, single interlayer cation doping alone may not fully confer a material with favorable Zn 2+ storage performance. Therefore, the introduction of mixed interlayer cations could be a viable approach to further enhance the electrochemical properties of hydrated vanadium pentoxide …”

“…Therefore, the introduction of mixed interlayer cations could be a viable approach to further enhance the electrochemical properties of hydrated vanadium pentoxide. 40 Herein, a one-step hydrothermal approach to preparing V 2 O 5 • 3H 2 O (VO) coinserted by Ni 2+ and NH 4 + , i.e., NNVO, is reported. The synergistic "pillar" effect of Ni 2+ and NH 4 + successfully makes the interlayer spacing of V 2 O 5 enlarged, thereby accelerating ion diffusion and meanwhile stabilizing the crystal structure.…”