Current Progress In Vanadium Oxide Nanostructures And Its .
-of-nanotechnology-and-nanomaterialsJournal of Nanotechnology and NanomaterialsReview ArticleCurrent Progress in Vanadium Oxide Nanostructures and ItsComposites as Supercapacitor ElectrodesRaktima Basu*, Sandip Dhara*Surface and Nanoscience Division, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute,Kalpakkam-603102, India*Correspondence should be addressed to Raktima Basu; raktimabasu14@gmail.com, S. Dhara; dhara@igcar.gov.inReceived date: August 27, 2020, Accepted date: October 12, 2020Copyright: 2020 Basu R, et al. This is an open-access article distributed under the terms of the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and sourceare credited.AbstractIn recent years, vanadium oxides have gained immense attention in the field of energy storage devices due to their low-cost, layeredstructure and multi-valency despite their limited electrical conductivity and lower structural stability. In this brief review, we havefocused on electrochemical properties of the stoichiometric vanadium oxides along with VOx composites. The morphology engineering,doping with heteroatom and formation of composites with carbon-based materials and/or conducting polymers in enhancing thesupercapacitive performances of the vanadium oxides are discussed in detail. Finally, the potentiality and challenges of vanadiumoxides nanocomposites for supercapacitor applications are discussed.Keywords: Supercapacitor, Vanadium oxide, Specific capacitance, Pseudocapacitance, Phase transitionIntroductionIn recent time, supercapacitors (SCs) are one of theemerging technologies used for clean energy prospect.The higher power density, low specific energy, longercycle life, and environmental affability made the SCssuperior compared to conventional batteries. However,the scientific community is working towards increasingthe specific energy of SCs by finding a suitable electrodematerial. Carbon materials, conducting polymers, andmetal oxide or hydroxides are reported to be suitablecandidates as electrodes for SC [1-3]. Carbon materialssuch as activated carbon, carbon nanotube and grapheneprovide excellent electrical conductivity and chemicalstability [4], however, they come with narrow chargestorage capacity and relatively low energy density [1]. Onthe other hand, the conducting polymers are a good choiceas a pseudocapacitor [3]. Nevertheless, the electrochemicalstability of conducting polymer is poor. Towards this end,transition metal oxides (TMOs) are alternative candidatesdue to their multiple oxidation states and rapid redoxkinetics [2,5-7]. Amongst other TMOs [8-10], vanadiumoxides have received recent attention owing to their lowcost, variety of valence states, and abundant sources [11-J Nanotechnol Nanomaterials. 2020Volume 1, Issue 313]. V is a transition metal ([Ar]3d34s2) with valences inthe range of 2 to 5 with major oxides as VO, V2O3, VO2,and V2O5 [14]. However, the V-O phase diagram comprisesmixed-valence oxides comprehending two oxidationstates, e.g. V4O9, V6O13, V8O15, V7O13, V6O11, among otherswhich permit conversion between oxides of differentstoichiometry easily and make it unstable during chargingdischarging cycle. As the composition, oxidization state,and structural phase of a material have a significant role onelectrochemical properties; the exchange of valency alongwith structural instability for these materials result in poorelectrochemical and cycle performance. Issues related to thepresence of multiple valence states of V [13], as well as itsstability affecting retention of capacitance and its efficiency,are found to hinder further utility in SCs. The poor chargestorage properties and electrical conductivity of vanadiumoxides are reported to be succeeded by fabricating directly onthe current collector, doping element, or by nanostructureengineering. There are several reports on SC propertiesof VOx composites as well as individual vanadium oxidessuch as VO2, V2O3, and V2O5 [3,15-26]. In this context, thismini review presents a summary of recent developmentsin vanadium oxide based supercapacitor along with futuredevelopments, prospects, and challenges.92
Basu R, Dhara S. Current Progress in Vanadium Oxide Nanostructures and Its Composites as SupercapacitorElectrodes. J Nanotechnol Nanomaterials. 2020; 1(3): 92-103.Electrochemical Properties of Vanadium of 1 A·g 1 for VO2 nanosheets in an organic gel electrolyte(1 M LiClO4 in propylene carbonate) with nearly 82%Dioxidecapacitance retention.Vanadium dioxide (VO2) is known to be stabilized indifferent polymorphs, including VO2(A), VO2(B), VO2(C),VO2(D), among others. [27]. Among the VO2 polymorphs,VO2(B) attracts much attention for its well known MIT at atechnologically important temperature of 340K, which isvery close to room temperature [28]. VO2(B) crystallizes inrutile tetragonal (R; space group P42/mnm) and monoclinic(M1; space group P21/c) structure above and below thetransition temperature, respectively [29,30]. In the hightemperature R phase, V atoms are equally spaced, forminglinear chains along the cR axis with each V atom surroundedby an oxygen octahedron [31]. The lattice parameters arecR 2.85 Å, and aR bR 4.55 Å. Whereas in lowtemperature monoclinic phase, the volume of the unit cellbecomes double than that of R phase with latticeparameters aM1 5.70 Å, bM1 4.55 Å, cM1 5.38 Å, and ßM1 123 [32]. The approximate crystallographic relationshipbetween M1 and R phase is aM1 2cR, bM1 aR, and cM1bR- cR [33]. In the M1 phase, there are significant differencesin the arrangement of V along cR axis. The V atoms formpair, and the pairs tilt along the cR axis making thesurrounding octahedron deformed. Besides M1, two moremetastable phases of monoclinic M2 having space groupC2/m and triclinic T (alternatively monoclinic M3) withspace group C͞ 1 are also reported in the process of thephase transition from M1 to R [34].There are several reports on the supercapacitiveperformance of VO2(B) in the M1 phase. However, its lowrate capability and cycling instability become obstacles toserve as a commercial supercapacitor. The modificationin structure designing has been adopted to overcome thebarrier. Zhang et al. [35] prepared template-free 3D hollowspherical cages (shown in figures 1a-b) by hydrothermalmethod, which showed a specific capacitance of 1175mF·cm 2 (336 F·g 1) with adequate stability, and 68% ofthe capacitance was retained after 10,000 cycles.However,2D nanosheet of VO2 is reported to be a more eligiblecandidate for electrochemical performance than that ofits 3D counterpart because of large specific surface areashortening the diffusion path of ion and thereby enhancingthe redox reaction. Ndiaye et al. [36] obtained specificcapacitance of 663 F·g 1 at the scan rate of 5 mV·s 1 andexcellent cycling stability after 5000 cycles at the currentdensity of 10 A·g 1 for VO2 nanosheets. The 2D nanosheets(Figures 1c and 1d), while assembled with the structure ofcarbonized iron-polyaniline (C-FP), exhibited a specificcapacity of 47 mAh·g 1 at a current density of 1 A·g 1 [37].In 2D nanosheets, a large specific surface area diminishesthe path length of the ion diffusion enabling the executionof the redox reaction effectively. Rakhi et al. [38] reporteda specific capacitance of 405 F·g 1 at the current densityJ Nanotechnol Nanomaterials. 2020Volume 1, Issue 3Figure 1: Scanning electron micrograph of (a-b) VO23D hollow spherical cages and its higher magnificationimage; marked circles show broken area [Reprintedwith permission from Ref. 36, Copyright 2018 @ RoyalSociety of Chemistry] (c-d) 2D VO2 nanosheet and itszoomed image [Reprinted with permission of authorsfrom Ref. 37, Copyright 2019 @ American Institute ofPhysics], (e) VO2 nanoporous structure grown on carbonpaper, (f) bare C fiber [Reprinted with permissionof authors from Ref. 40, Copyright 2019 @ NaturePublishing Group].The thin layer of 1D VO2 nanorods on indium tin oxide coated glass substrates are also reported [39] to produce aspecific capacitance of 486 mF·cm 2 at the scan rate of 10mV·s 1. Nie et al. [22] reported VO2@Polyaniline coaxialnanobelts exhibiting a higher specific capacitance of 246F·g-1 at 0.5 A g-1 than that of VO2 nanobelts (160.9 F·g-1).The specific capacitance was almost constant at around118 mF·cm 2 after 5000 cycles at the scan rate of 100mV·s 1. VO2 nanoporous structures on carbon fiber in theM1 phase (Figures 1e and 1f) exhibit a specific capacitanceof 20.7 mF·cm 2 at the current density of 0.3 mA·cm 2 [40].93
Basu R, Dhara S. Current Progress in Vanadium Oxide Nanostructures and Its Composites as SupercapacitorElectrodes. J Nanotechnol Nanomaterials. 2020; 1(3): 92-103.Figure 2: (a) Areal capacitance versus scan rate and (b) capacitance retention with charge-discharge cycle of pureM1 (S1), and mixed phases of VO2 (S2 and S3) [Reprinted with permission of authors from Ref. 40, Copyright 2019@ Nature Publishing Group].It also demonstrates capacitance retention of 93.7% andcoulombic efficiency of 98.2% for 5000 charge-dischargecycles. However, the similar nanoporous structures inM2 and T phases of VO2 show poor specific capacitance(Figure 2a) as well as cyclic stability (Figure 2b) because ofmixed valency [40].Another way to enhance the electrochemical performanceof VO2 is by combining with carbon materials, whichimprove the electrical conductivity. VO2 nanoflowers on 3Dgraphene (3DG) networks were reported to exhibit a largespecific capacitance of 466 mF·cm 2, capacitance retentionof 63.5% after 3000 cycles by Wang et al. [41]. Ren etal. [42] synthesized VO2 nanoparticles on edge-orientedgraphene foam (EOGF) which exhibit a capacitance of119 mF·cm 2 at the scan rate of 2 mV·s 1. The VO2(B)/carbon core-shell composites prepared by Zhang et al.[43] exhibited a specific capacitance of 203 F·g 1 at thecurrent density of 0.2 A·g 1. Lv et al. [44] prepared VO2(B)nanobelts/rGO composites with a porous framework,which showed an excellent power density of 7152 W·kg 1 atthe energy density of 3.13 Wh·kg 1. Shao et al. [23] reportedVO2 demonstrating superior properties as supercapacitorcompared to that for the V2O5, which was well known for itsSC performance. It is due to higher electronic conductivityin VO2, as compared to V2O5, originating from a mixedvalence and structural stability because of the increasededge sharing and the consequent resistance to latticeshearing during cycling [45]. The comparison of variousVO2 based supercapacitors and their synthesis proceduresare shown in Table 1.Nanostructures(Growth sityCycling stability(%)Ref.VO2 (B) hollow spheres(Solvothermal)1 M Na2SO4/critical micelleconcentration336 F·g 12mA·cm 268% (10000 cycles)[36]VO2 nanosheets(Solvothermal)6 M KOH663 F·g 110 A·g 199.4% (9000 cycles)[37]VO2 nanosheets (Solvothermal)6 M KOH47 mAh·g 11 A·g 189% (10 000 cycles)[37]VO2 nanosheet(Solution Reduction ofhydrothermally exfoliated bulkV2O5)1 M LiClO4/PPC405 F·g 11 A·g 182% (6000 cycles)[38]J Nanotechnol Nanomaterials. 2020Volume 1, Issue 394
Basu R, Dhara S. Current Progress in Vanadium Oxide Nanostructures and Its Composites as SupercapacitorElectrodes. J Nanotechnol Nanomaterials. 2020; 1(3): 92-103.VO2 nanorod thin films(RF magnetron sputtering)0.1 M NaOH486 mF·cm 210 mV·s 1100% (5000 cycles)[39]VO2@Polyaniline coaxialnanobelts(Reactive templated organiclayer on solvothermally grownVO2nanobelt)0.5 M Na2SO4246 F. g-10.5 A. g-1(28.6%) (1000 cycles)[22]Nanoporous VO2(Vapour transport of bulk V2O5on C-paper)Na2SO420.7 mF·cm 20.3mA·cm 293.7% (5000 cycles)[40]VO2 NFs@3DG(Hydrothermally grown VO2 on3DG)0.5 M K2SO4507 F·g 13mA·cm 263.5% (3000 cycles)[41]VO2 nanoparticle/EOGF(Hydrothermally grown VO2 onEOGF)5 M LiCl119 mF·cm 22 mV·s 170% (1500 cycles)[42]VO2(B)/C core-shell(Single pot hydrothermal)1 M Na2SO4203 F·g 10.2 A·g 110.4% (100 cycles)[43]VO2(B) nanobelts/rGO(Hydrothermally grown VO2 onrGO)0.5 M K2SO4353 F·g 11 A·g 178% (10 000 cycles)[44]Table1: Comparison of various VO2 based supercapacitors.Electrochemical Properties of Vanadium (space group I2/a) [47].TrioxideVanadium trioxide (V2O3) revels a rhombohedralcorundum structure at room temperature, (space groupR3̅c ) [46], where the V atoms pair along the crystal c-axisand form honeycomb lattices in the ab-plane. Whereas,below the temperature 150 K, a paramagnetic metallic toan antiferro-magnetic insulating transition happens alongwith the structural transition to the monoclinic phaseThere are very few reports on the electrochemicalstudies on V2O3, mostly because of the poor stability ofthis material. A binder-free electrode of V2O3 nanoflakeson N-doped rGO (Figure 3a) was reported to have anareal capacitance of 216 mF·cm 2 at a current density of 1mA·cm 2 (Figure 3b). It also exhibits cycling stability withretention of 81% of the initial capacitance value after10,000 cycles (Figure 3c) [48].Figure 3: (a) Scanning electron micrograph of the V2O3/N-rGO samples, (b) The galvanostatic charge-discharge(GCD) curves obtained for the self-supported V2O3/N-rGO film electrodes at different current densities. (c) Cyclingstability for 10000 cycles [Reprinted with permission from Ref. 48, Copyright 2017 @ Royal Society of Chemistry].J Nanotechnol Nanomaterials. 2020Volume 1, Issue 395
Basu R, Dhara S. Current Progress in Vanadium Oxide Nanostructures and Its Composites as SupercapacitorElectrodes. J Nanotechnol Nanomaterials. 2020; 1(3): 92-103.Nanostructures(Growth sityCycling stability(%)Ref.V2O3/N-rGO nanoflakes(500 oC NH3 reduction of V2O5 gel/GO films)1 M Na2SO4216 mF·cm 21 mA·cm 281% (10000 cycles)[48]V2O3/C nanocomposites(Calcination of hydrothermallygrown (NH4)2V3O8)5 M LiCl458.6 F·g 10.5 A·g 186% (1000 cycles)[49]V2O3@C core-shell nanorods(Single pot hydrothermal processusing V2O5 nanorod)5 M LiCl228 F·g 10.5 A·g 186% (1000 cycles)[50]V2O3 nanofoam@activated carbon(Calcination of NH4VO3 solutionand activated C)1 M NaNO3185 F·g 10.05 A·g 149% (100 cycles)[51]Table 2: Comparison of various V2O3 based supercapacitors.However, V2O3 combined with carbon compositesare reported to serve as superior electrode material.Zheng et al. reported V2O3/C composites exhibitinghigh pseudocapacitance of 458.6 F·g 1 at 0.5 A·g 1. Thecomposite also shows a retention rate of 86% after 1000cyclesin aqueous electrolyte [49]. Hu et al. [50] synthesizedV2O3@C core-shell nanorods with porous structureswhich exhibited 228, 221, 207, 158, and 127 F·g 1 specificcapacitances at current densities of 0.5, 1, 2, 5, and 10 A·g 1,respectively. Zhang et al. [51] reported a V2O3 nanofoam@activated carbon composite, which showed a specificcapacitance of 185 F·g 1 at 0.05 A·g 1. The comparison ofvarious V2O3 based supercapacitors, fabricated followingdifferent process steps, are shown in Table 2.Electrochemical Properties of VanadiumPentoxideVanadium pentoxide (V2O5) stabilizes in various phasesincluding α-V2O5, β-V2O5, δ-V2O5, γ′-V2O5, ζ-V2O5, and ε′V2O5 [52]. The most well-known phase is α-V2O5, whichcrystallizes into an orthorhombic structure composed ofweakly Van der Walls bonded layers of VO5 pyramidssharing their vertices and corners [53,54]. The unit-cellparameters are a 11.51 Å, b 3.56 Å, and c 4.37 Å [53]. ) with distorted squareIt has space group Pmmn, (𝐷𝐷 pyramidal coordination symmetry around each V atom.There are three non-equivalent oxygen atoms in each unitcell (denoted as OI, OII, and OIII). OI is the terminal(vanadyl) oxygen with two different bond lengths. One ofthem is a strong and short V-OI bond with a length of 1.577Å (d1). Another one is large and weak Van der Waals typeconnecting two adjacent layers in the V2O5 structure, witha bond length of 2.793 Å. Both of these OI atoms orientJ Nanotechnol Nanomaterials. 2020Volume 1, Issue 3almost along the c-axis. The two-fold coordinated bridgingoxygen (OII) connects two adjacent V atoms with V-OIIbond length of 1.78 Å (d2). The ladder-shaped OIII atomsare the three-fold coordinated oxygen with three differentV-OIII bond lengths of 1.88 (d3), 1.88 (d3), and 2.02 Å (d4)[53].The SC properties in V2O5 is reported to be superior toother vanadium oxides because of its stability and layeredstructure [19,21-23]. Yang et al. [55] prepared hollow V2O5spheres which showed an excellent capacitance of 479 F·g 1at 5 mV·s 1. V2O5 nanofibers showed specific capacitanceof 190 F·g 1 in aqueous electrolyte (KCl) and 250 F·g 1in the organic electrolyte (LiClO4 in PPC) as reported byWee et al. [56]. Apart from supercapacitor performance,the change in electrolytes in case of V2O5 also controls itsmechanical stability and chemical dissolution. Pandit etal. [57] synthesized V2O5 thin film on a pliable stainlesssteel substrate which was reported to exhibit a highspecific capacitance of 735 F·g 1 at 1 mV·s 1 with capacitorsretention of 71% after 1000 cycles.The rGO/V2O5 composites showed specific capacitanceof 386, 338, 294, 241, and 197 F·g 1 at current densityof 0.1, 0.2, 0.5, 1, and 2 A·g 1, respectively, as reportedby Liu et al. [58]. However, 2D heterostructures of V2O5nanosheets growing on rGO flakes showed relativelyhigh specific capacitance of 653 F·g 1 at 1 A·g 1 and cyclicstability of 94% after 3000 cycles [59]. Choudhury et al.[60] prepared V2O5 nanofiber (VNF)/exfoliated graphenenanohybrid with the mass ratio of 1:0.25 and 1:0.5 with asuperior capacitance value of 218 F·g 1 at 1 A·g 1 for 1:0.5mass ratio. Balasubramanian et al. [61] reported floweryV2O5 structures coated with carbon showing specific96
Basu R, Dhara S. Current Progress in Vanadium Oxide Nanostructures and Its Composites as SupercapacitorElectrodes. J Nanotechnol Nanomaterials. 2020; 1(3): 92-103.Figure 4: (a) Scanning electron micrograph of V2O5 aerogel and diameter distribution of V2O5 nanofibers (inset)(b) Specific capacitance as a function of current density for raw V2O5 powder, MWCNTs, V2O5 aerogel and hybridaerogel of V2O3/C nanocomposites (VMA-30) [Reprinted with permission from Ref. 63, Copyright 2015 @ RoyalSociety of Chemistry].capacitance of 417 F·g 1 at a current density of 0.5 A·g 1.Chen et al. [62] synthesized V2O5 nanocomposites withcarbon nanotubes (CNT) which provided a capacity of 228C·g 1 between 1.8 and 4.0 V. Wu et al. [63] reported V2O5/multi-walled CNT core/shell hybrid aerogel (Figure 4a),which demonstrated the maximum specific capacitanceof 625 F·g 1 with outstanding cycle performance ( 20000cycles). The hybrid aerogel showed better performancethan that of raw V2O5 powder, MWCNTs, and V2O5 aerogel(Figure 4b).However, the insertion of nitrogen atoms into the carbonnetwork enhances the electrochemical performance byrestraining the hydrophobicity. Sun et al. [64] reportedself-assembled 3D N-carbon nanofibers (CNFs)/V2O5aerogels showing the specific capacitance of 575.6 F·g 1even after 12,000 cycles (97% of the initial value). V2O5also have been combined with conducting polymers e.g.,polypyrrole (PPy), poly (3, 4-ethylenedioxythiophene)(PEDOT), and polyaniline (PANI), to enhance theelectrical conductivity and prevent the V from dissolving.Qian et al. [65] reported 3D V2O5/PPy nanostructures,which exhibited a high specific capacitance of 448 F·g 1.However, Bi et al. [66] showed a comparative study withoxygen vacancy (Ö) resulting with the specific capacitanceof 614 F·g 1 for VÖ-V2O5/PEDOT higher than that of 523F·g 1 for VÖ-V2O5/PANI and 437 F·g 1 for VÖ-V2O5/PPy(Figures 5a and 5b).Figure 5: (a) CV curves of V VÖ -V2O5/Conducting polymers and V2O5-NF at a scan rate of 5 mV. s-1. (b) galvanostaticcharge-discharge curves of VÖ-V2O5/ Conducting polymers and V2O5-NF at a current density of 0.5 A. g 1 [Reprintedwith permission from Ref. 66, Copyright 2019 @ Royal Society of Chemistry].J Nanotechnol Nanomaterials. 2020Volume 1, Issue 39
Basu R, Dhara S. Current Progress in Vanadium Oxide Nanostructures and Its Composites as Supercapacitor Electrodes. J Nanotechnol Nanomaterials. 2020; 1(3): 92-103. J Nanotechnol Nanomaterials. 2020 Volume 1, Issue 3 93 Electrochemical Properties of Vanadium Dioxide Vanadium dioxide (VO 2) is known to be stabilized in different polymorphs .
Ferro Vanadium is a universal hardener, strengthener and anti-corrosive additive for steels like high-strength low-alloy (HSLA) steel, tool steels, as well as other ferrous-based products. Ferro vanadium belongs to the category of ferroalloy. Ferro vanadium is an alloy which is formed by combining iron and vanadium.
vanadium and nickel. Depending on the origin of crude oil, the concentration of the vanadium varies from as low as 0.1 ppm to as high as 1200 ppm, while that of nickel commonly varies from trace to 150 ppm [5-8]. Vanadium compounds present in the saleable oil create vanadium
demand charges and four hour capacity, it is clear the industry is continuously moving towards energy storage with longer and longer duration. . Vanadium Redox, the most common redox flow battery technology on the market, uses the oxidation states of vanadium. Vanadium redox batteries are limited by the high cost of vanadium and by the
(55 m2/g) obtained from Degussa (P-25), -y-A1203 (180 m2/g) obtained from Harshaw, and SiO, (300 m2/g) Cab-o-sil. Sample preparation: Vanadium tri-isopropoxide oxide (Alfa) was used as the precursor. The samples were made by incipient wetness impregnation of the
2. Group II (vanadium group): This group was given a standard feed and water containing 0.3 mg/mL of vanadium (IV) chloride (Sigma-Aldrich, St. Louis, MO, USA) for 4 weeks. 3. Group III (diabetic group): After being melt in 0.1 M sitrat buffer at 4.5 pH, streptozotocin (STZ) 60 mg/
Oct 17, 2018 · CO) O, and (CF 3 CO) 2 O as shown in Scheme 1. These promoters are difficult to handle and used in excess amounts to facilitate the reaction. In contrast, vanadium facilitated reactions are feasible and afford excellent yield, depending on the vanadium source (V 2 O 5, VO(acac) 2,
graphite and vanadium; (iii) competition from other suppliers of graphite and vanadium; (iv) government regulation of the mining industry in the United States;(v) operating conditions at our mining projects; (vi) the world -wide supply and demand of graphiteand vanadium, (vii) weather conditions; (viii) unanticipated geological,
Astrophysics also receives tactical-level advice from the external science community via the Astrophysics Subcommittee of the NASA Advisory Council, and advice on cooperative activities from the Congressionally chartered, National Science Foundation (NSF)-managed Astronomy and Astrophysics Advisory Committee. NASA enables research to understand the structure, content, and evolution of the .
