Enhanced Intercalation Dynamics and Stability of Engineered Micro/Nano‐Structured Electrode Materials: Vanadium Oxide Mesocrystals

Abstract

An additive and template free process is developed for the facile synthesis of VO2 (B) mesocrystals via the solvothermal reaction of oxalic acid and vanadium pentoxide. The six-armed star architectures are composed of stacked nanosheets homoepitaxially oriented along the [100] crystallographic register with respect to one another, as confirmed by means of selected area electron diffraction and electron microscopy. It is proposed that the mesocrystal formation mechanism proceeds through classical as well as non-classical crystallization processes, and is possibly facilitated or promoted by the presence of a reducing/chelating agent. The synthesized VO2 (B) mesocrystals are tested as a cathodic electrode material for lithium-ion batteries, and show good capacity at discharge rates ranging from 150-1500 mA g(-1) and a cyclic stability of 195 mA h g(-1) over fifty cycles. The superb electrochemical performance of the VO2 (B) mesocrystals is attributed to the porous and oriented superstructure that ensures large surface area for redox reaction and short diffusion distances. The mesocrystalline structure ensures that all the surfaces are in intimate contact with the electrolyte, and that lithium-ion intercalation occurs uniformly throughout the entire electrode. The exposed (100) facets also lead to fast lithium intercalation, and the homoepitaxial stacking of nanosheets offers a strong inner-sheet binding force that leads to better accommodation of the strain induced during cycling, thus circumventing the capacity fading issues typically associated with VO2 (B) electrodes.

Ionic liquid-modulated preparation of hexagonal tungsten trioxide mesocrystals for lithium-ion batteries

“…[5][6][7][8][9][10][11][12] Considering that mesocrystals often display inherent and uniform porosity associated with well-defined nanoparticle orientation, mesocrystals could be exceedingly beneficial when used as electrode for lithium-ion batteries because of more prevalent and uniform pores that ease intercalation by decreasing the Li + ion diffusion distance and pathways. [13][14][15][16][17][18][19][20][21] However, it should be noted that attempts to fabricate the mesocrystalline electrodes are challenged due to their thermodynamically metastable feature. Usually, polymer additives are employed to temporarily stabilize the nanoparticle subunits in order to obtain highly stable mesocrystals.…”

Microstructurally Composed Nanoparticle Assemblies as Electroactive Materials for Lithium-Ion Battery Electrodes

“…Indexing the SAED pattern revels that . Reprinted with permission from Uchaker et al [127]. Copyright 2013 John Wiley & Sons, Inc the individual VO 2 (B) nanosheets exhibit preferential growth along the [010] direction, indicating that the (010) plane has a relatively high stacking rate that is realized by considering the relative stacking rate of the octahedra at various crystal faces [128].…”

“…Monoclinic nanostructured metastable vanadium dioxide, VO 2 (B), was synthesized from the reduction of commercially available V 2 O 5 utilizing additive-free solution-based processing methods where oxalic acid served as both the reducing and chelating agent due to its disposition to serve as a bidentate ligand [127]. The size and morphology of the as-prepared VO 2 (B) material was examined using SEM, Fig.…”

Nanostructured layered vanadium oxide as cathode for high-performance sodium-ion batteries: a perspective

“…Various novel VO 2 (B) nanostructures have been reported, such as VO 2 (B) nanospheres, [23] nanowires, [24] nanosheets, [25] nanowires assembled hollow spheres, [26] and micro/nano-structured nanoparticles. [27] It should be noted that, in a typical heat treatment or solution reaction process, VO 2 (B) trends to transform into monoclinic phase VO 2 (M) The reaction during charge/discharge can happen between Na 0.3 VO 2 and NaVO 2 [28] Graphene quantum dots coated VO 2 arrays 306 mA h/g at 100 mA/g A capacity of more than 110 mA h/g after 1500 cycles at 18 A/g A binder-free cathode by bottom-up growth of biface VO 2 arrays directly on a graphene network was achieved [29] Carbon quantum dots coated VO 2 nanowires 328 mA h/g at 0.3 C A capacity of 133 mA h/g even at the rate of 60 C…”