Zinc pyrovanadate nanosheets of atomic thickness: excellent Li-storage properties and investigation of their electrochemical mechanism

Abstract

Exploring ternary metal oxides that can in situ form an elastic medium to accommodate the volume changes upon lithium intercalation is now a popular and effective way to achieve high-performance lithium ion battery with enhanced cycling stability. Herein, we report an ultrathin zinc pyrovanadate nanosheet of atomic thickness with exposed (001) facets via a facile hydrothermal method. Morphological and structural evolutions of the zinc pyrovanadate are investigated to reveal the electrochemical reaction mechanism of this compound towards lithium ions intercalations for the first time. It is found that the initial zinc pyrovanadate transform into ZnO nanoparticles and LiV 2 O 5 in the first cycle, and the subsequent reaction mainly occurs between ZnO and LiZn and lithiation/delithiation of the lithium vanadate. Interestingly, the in situ formed lithiated vanadate matrix could serve as a conductive network for reversible electrochemical process of ZnO. The ultrathin thickness is in favour of shortening pathway for lithium ions, while the specific exposed facets are facilitated to form the architecture of ZnO nanoparitcles embedded in amorphous lithiated vanadate matrix owing to the sandwich-like skeleton of zinc pyrovanadate that is constructed from the layer-by-layer stacking of the [ZnO 6 ] and [V 2 O 7 ] polyhedra chains projected along the c axis. Benefits from these inspiring merits, the as-synthesized ultrathin zinc pyrovanadate nanosheet exhibits a high specific capacity (963 mAh/g at 0.05 A/g), outstanding rate capability (344 mAh/g at 10 A/g), and long cycle life (602 mAh/g could be maintained after 980 cycles at 1 A/g), and is regarded as a promising candidate of lithium ion battery anode material.

Rechargeable Aqueous Zinc‐Ion Battery Based on Porous Framework Zinc Pyrovanadate Intercalation Cathode

“…It is clear that all the diffraction peaks can be indexed to Zn 3 V 2 O 7 (OH) 2 ·2H 2 O (JCPDS 50‐0570), indicating that single‐phase ZVO has been formed. It is interesting to note that the XRD intensity ratio I (001)/ I (012) of the ZVO prepared by our process shows a dramatic enhancement in comparison to hydrothermally synthesized ZVO nanosheets, nanoplates, and microflowers . Moreover, the preferential orientation of ZVO made by our process along the [001] direction ( c ‐axis) may provide better access for guest Zn 2+ ions into the available sites.…”

The kinetic investigation of Zn3(OH)2V2O7•2H2O nanosheets at various conditions by In-situ Electrochemical Impedance Spectroscopy

“…The result of SEM investigation was accordance with the above XRD data, which can be explained based on the Ostwald ripening and growth mechanism (15) . Combined with XRD analysis and the previous report (10) , it can be referred that facts vertical to the 2D plane is (001). All the particles for ZVO-24 showed a well defined regular hexagonal and the surface became more smooth, which was stemmed from the inherent anisotropic nature of Zn3(OH)2V2O7•2H2O (7,14) .…”

“…the first three discharge and charge curves of the obtained samples at 1.0 A g -1 in 0.01-3.0 V. The open circuit voltage (OCV) of the fresh cell was about 2.85 V. The voltage profiles are indicative of typical lithium storage characteristics of Zn3(OH)2V2O7•2H2O(5,10) . During the initial discharge, the quick decreased process from 2.85 to 0.70 V can be assigned to the irreversible lithium insertion (Eq.(5)).…”

“…With the further help of graphene networks, Zn3(OH)2V2O7•2H2O nanoplates delivered an enhanced reversible capacity of 854 mAh g -1 after 400 cycles at 500 mA g -1 (9) . Wang et al discussed the electrochemical reaction mechanism of Zn3(OH)2V2O7•2H2O nanosheets during the first cycle (10) . However, these works were mainly focused on the synthesis, coating, morphology regulation, structure and lithium storage capacity, etc.…”

Synthesis of a three-dimensional cross-linked Ni–V2O5 nanomaterial in an ionic liquid for lithium-ion batteries

“…11,12 Therefore, transition-metal vanadates are considered to be potential anode materials for lithium-ion batteries. [13][14][15][16][17][18][19][20][21] The vanadate materials that have been most widely studied to date are nickel vanadate, cobalt vanadate and manganese vanadate. [22][23][24][25][26][27] Among these, nickel vanadate electrode materials (e.g.…”