The issue of water molecule activity in aqueous zinc-ion batteries presents a significant challenge.During the charging and discharging process,the strong polarity of water molecules tends to cause the dissolution of ...The issue of water molecule activity in aqueous zinc-ion batteries presents a significant challenge.During the charging and discharging process,the strong polarity of water molecules tends to cause the dissolution of cathode materials,which reduces the cycle stability and specific capacity,consequently limiting the practical application of zinc-ion batteries.In this work,hydroxypropylβ-cyclodextrin(HP-β-CD),a special stereo cyclic organic molecule with hydrophobic inner cavity and hydrophilic outer cavity,is used as the intercalator for hydrated vanadium oxide(VOH)to enlarge the layer spacing and enhance the hydrophobicity of the cathode material.The larger interlayer spacing(13.9Å)of HP-β-CD-VOH is beneficial for improving ion mobility and the intrinsic electrochemical reaction kinetics.HP-β-CD-VOH delivers a discharge capacity of 336.7 mAh g^(-1)at 0.2 A g^(-1)and high-rate capability(242 mAh g^(-1)at 5 A g^(-1)).Due to the hydrophobic property of HP-β-CD in the interlayer pillar,the vanadium dissolution effect of polar water molecules can be reduced during charge and discharge;HP-β-CDVOH demonstrates sustained high efficiency and extended cycle longevity,maintaining a remarkable durability of 6000 cycles at a current density of 10 A g^(-1).This study presents an effective strategy for developing high-performance aqueous zinc-ion battery cathode materials.展开更多
Vanadium oxide(VO_(x))has garnered significant attention in the realm of resistive random-access memory(RRAM)owing to its outstanding resistive switching characteristics.However,the ambiguous mechanisms of resistive s...Vanadium oxide(VO_(x))has garnered significant attention in the realm of resistive random-access memory(RRAM)owing to its outstanding resistive switching characteristics.However,the ambiguous mechanisms of resistive switching and inferior stability hinder its practical applications.Herein,an RRAM named VO_(x)/TiO_(2)/n^(++)Si device is prepared.It displays bipolar resistive switching behavior and shows superior cycle endurance(>200),a significantly high on/off ratio(>10^(2))and long-term stability.The tremendous improvement in the stability of the VO_(x)/TiO_(2)/n^(++)Si device compared with the Cu/VOx/n^(++)Si device is due to the p-i-n structure of VO_(x)/TiO_(2)/n^(++)Si.The switching mechanism of the VO_(x)/TiO_(2)/n^(++)Si device is attributed to the growth and annihilation of Cu conductive filaments.展开更多
Ni-ion aqueous batteries(NIBs)were considered an important development direction for aqueous batteries due to the high theoretical capacity(913 mA h g^(-1))and volume capacity(8136 mA h cm^(-3))of nickel metal.Herein,...Ni-ion aqueous batteries(NIBs)were considered an important development direction for aqueous batteries due to the high theoretical capacity(913 mA h g^(-1))and volume capacity(8136 mA h cm^(-3))of nickel metal.Herein,an electrolyte additive(dodecyl trimethyl ammonium chloride,DTAC)was used to improve the electrolyte environment,achieve efficient transport of Ni-ion,and combine the intercalated vanadium oxide cathodes to realize novel strategy NIBs.Firstly,the introduction of trace amounts of DTAC improved the high-concentration NiCl_(2)(4.2 M)electrolyte environment and reconstructed the hydrogen bond network.Molecular dynamics(MD)calculations and electrochemical results indicated that DTAC contributed to the desolvation process of Ni^(2+)and the realization of fast dynamics.The results of Ni symmetric cells demonstrated that DTAC enhanced the rapid migration of Ni-ion and achieved longer cycling stability(1750/1500 h at 0.2/0.5 mA cm^(-2)without obvious short circuits).Secondly,the insertion of organic small molecules(pyrrolidine)into vanadium oxide(V_(2)O_(5))to expand the interlayer spacing promoted the Ni-ion storage capacity of the cathodes.The capacity retention rate of Ni full battery after 6000 cycles at 5 A g^(-1)reached 82.17%.This work provided a novel strategy for the development of Ni-ion aqueous batteries.展开更多
Although the enhancement of the zinc storage performance of layered vanadium oxides can be realized by the ionic pre-intercalation strategy,it also occupies a large number of active sites and thus fails to release the...Although the enhancement of the zinc storage performance of layered vanadium oxides can be realized by the ionic pre-intercalation strategy,it also occupies a large number of active sites and thus fails to release the full potential of vanadium oxides.Here,vanadium oxide nanobelts with sodium-poor and oxygen defect-rich were constructed by regulating the content of pre-embedded sodium ions to strike a balance between pre-embedded ions and structural stability.The introduction of trace sodium ions not only increases the spacing of vanadium oxide layers but also occupies as few active sites as possible,which provides the possibility of massive storage,rapid diffusion and stabilization of the host structure for zinc ions.Moreover,the abundant oxygen defects transform the ion transport pathway from two-dimensional to three-dimensional,which greatly improves the ion transport rate in the host phase.Due to these advantages,the synthesized vanadium oxide nanobelts exhibit remarkable electrochemical properties,and this work provides a new idea for the design of structurally stable layered vanadium oxides with excellent properties.展开更多
Pre-intercalation is the mainstream approach to inhibit the unpredicted structural degradation and the sluggish kinetics of Zn-ions migrating in vanadium oxide cathode of aqueous zinc-ion batteries(AZIBs),which has be...Pre-intercalation is the mainstream approach to inhibit the unpredicted structural degradation and the sluggish kinetics of Zn-ions migrating in vanadium oxide cathode of aqueous zinc-ion batteries(AZIBs),which has been extensively explored over the past 5 years.The functional principles behind the improvement are widely discussed but have been limited to the enlargement of interspace between VO layers.As the different types of ions could change the properties of vanadium oxides in various ways,the review starts with a comprehensive overview of pre-intercalated vanadium oxide cathode with different types of molecules and ions,such as metal ions,water molecules,and non-metallic cations,along with their functional principles and resulting performance.Furthermore,the pre-intercalated vanadium cathodes reported so far are summarized,comparing their interlayer space,capacity,cycling rate,and capacity retention after long cycling.A discussion of the relationship between the interspace and the performance is provided.The widest interspaces could result in the decay of the cycling stability.Based on the data,the optimal interspace is likely to be around 12?indicating that precise control of the interspace is a useful method.However,more consideration is required regarding the other impacts of pre-intercalated ions on vanadium oxide.It is hoped that this review can inspire further understanding of pre-intercalated vanadium oxide cathodes,paving a new pathway to the development of advanced vanadium oxide cathodes with better cycling stability and larger energy density.展开更多
The nanometer CeO2 powder was prepared by the method of microwave-assisted heating hydrolysis,and the nanometer CeO2-supported or ordinary CeO2-supported vanadia catalysts with different vanadium loadings(atomic ratio...The nanometer CeO2 powder was prepared by the method of microwave-assisted heating hydrolysis,and the nanometer CeO2-supported or ordinary CeO2-supported vanadia catalysts with different vanadium loadings(atomic ratios:100V/Ce=0.1,1,4,10,and 20) were prepared by an incipient-wetness impregnation method.Spectroscopic techniques(XRD,FT-IR,Raman and UV-Vis DRS) were utilized to characterize the structures of VOx/CeO2 catalysts.The results showed that the structures of CeO2-supported vanadium oxide catalysts de...展开更多
Rechargeable magnesium ion batteries are potential candidates to replace the lithium ion batteries due to their high volumetric energy density,dendrite free cycling,and low costs.In present work,we have critically rev...Rechargeable magnesium ion batteries are potential candidates to replace the lithium ion batteries due to their high volumetric energy density,dendrite free cycling,and low costs.In present work,we have critically reviewed the recent advances made in the field of cathode materials development to achieve the high reversible capacities and working potentials.In first part,carbon-based cathodes such as fluorinedoped graphene nanosheets and graphite fluoride(CF0.8)are discussed in terms of compatibilities of pos让ive electrode materials and electrolyte solutions for rechargeable magnesium-ion batteries.Whereas,the second part of this review focuses on crystal structure of vanadium oxide and its capability to accommodate the Mg^2+ions.Likewise,electrochemical performance of selected vanadium oxide based cathodes including VO2(B),FeVO4.0.9H2(X Mc)2.5+yVO9+δ,RFC/V2O5 and V2O5/Graphene composite,are discussed at different temperatures.To support the future research on magnesium ion batteries,particularly positive electrode material developments,several innovative research directions are proposed.展开更多
The emergency of high-power electrical appliances has put forward higher requirements for the power density of lithium-ion batteries.Vanadium oxides with large theoretical capacities and high operating voltages are co...The emergency of high-power electrical appliances has put forward higher requirements for the power density of lithium-ion batteries.Vanadium oxides with large theoretical capacities and high operating voltages are considered as prospective alternatives for the cathode of a new generation of lithium-ion batteries.However,the poor rate and cycling performance caused by the sluggish electrons/lithium transportation,irreversible phase changes,vanadium dissolution and large volume changes during the repeated lithium intercalation/deintercalation hinder their commercial development.Several optimizing routes have been carried out and extensively explored to address these problems.Taking V_(2)O_(5),VO_(2)(B),V_(6)O_(13),and V_(2)O_(3)as examples,this article reviewed their crystal structures and lithium storage reactions.Besides,recent progress in modification methods for the electrochemical insufficiencies of vanadium oxides,including nanostructure,heterogeneous atom doping,composite and self-supported electrodes has been systematically summarized and finally,the challenges for the industrialization of vanadium oxide cathodes and their development opportunities are proposed.展开更多
Aqueous Zn-ion batteries(ZIBs)hold great potential in large-scale energy storage systems due to the merits of low-cost and high safety.However,the unstable structure of cathode materials and sluggish(de)intercalation ...Aqueous Zn-ion batteries(ZIBs)hold great potential in large-scale energy storage systems due to the merits of low-cost and high safety.However,the unstable structure of cathode materials and sluggish(de)intercalation kinetics of Zn2+pose challenges for further development.Herein,highly reversible aqueous ZIBs are constructed with layered hydrated vanadium oxide as a cathode material.The electrochemical performances are further tested with the optimized electrolyte of 3M Zn(CF3SO3)2 and a cut-off voltage of 0.4 to 1.3 V,exhibiting a remarkable capacity of 290mAh g−1 at 0.5Ag−1,and long-term cycling stability at high current density.Furthermore,the Zn2+storage mechanism of V3O7⋅H2O is recognized as a highly reversible(de)intercalation process with good structural stability,implying the potential application in the field of large-scale energy storage.展开更多
Potassium-ion batteries(PIBs)have been considered as promising candidates in the post-lithium-ion battery era.Till now,a large number of materials have been used as electrode materials for PIBs,among which vanadium ox...Potassium-ion batteries(PIBs)have been considered as promising candidates in the post-lithium-ion battery era.Till now,a large number of materials have been used as electrode materials for PIBs,among which vanadium oxides exhibit great potentiality.Vanadium oxides can provide multiple electron transfers during electrochemical reactions because vanadium possesses a variety of oxidation states.Meanwhile,their relatively low cost and superior material,structural,and physicochemical properties endow them with strong competitiveness.Although some inspiring research results have been achieved,many issues and challenges remain to be further addressed.Herein,we systematically summarize the research progress of vanadium oxides for PIBs.Then,feasible improvement strategies for the material properties and electrochemical performance are introduced.Finally,the existing challenges and perspectives are discussed with a view to promoting the development of vanadium oxides and accelerating their practical applications.展开更多
Rechargeable aqueous zinc-ion batteries(ZIBs) have become a research hotspot in recent years,due to their huge potential for high-energy,fast-rate,safe and low-cost energy storage.To realize good electrochemical prope...Rechargeable aqueous zinc-ion batteries(ZIBs) have become a research hotspot in recent years,due to their huge potential for high-energy,fast-rate,safe and low-cost energy storage.To realize good electrochemical properties of ZIBs,cathode materials with prominent Zn^(2+) storage capability are highly needed.Herein,we report a promising ZIB cathode material based on electrochemically induced transformation of vanadium oxides.Specifically,K_(2) V_6 O_(16)·1.5 H_(2) O nanofibers were synthesized through a simple stirring method at near room temperature and then used as cathode materials for ZIBs in different electrolytes.The cathode presented superior Zn^(2+) storage capability in Zn(OTf)_(2) aqueous electrolyte,including high capacity of 321 mAh/g,fast charge/discharge ability(96 mAh/g delivered in 35 s), high energy density of 235 Wh/kg and good cycling performance.Mechanism analysis evidenced that in Zn(OTf)_(2) electrolyte,Zn^(2+) intercalation in the first discharge process promoted K_(2) V_6 O_(16)·1.5 H_(2) O nanofibers to transform into Zn_(3+x)V_(2) O_7(OH)_(2)·2 H_(2) O nanoflakes,and the latter served as the Zn^(2+)-storage host in subsequent charge/discharge processes.Benefiting from open-framework crystal structure and sufficiently exposed surface,the Zn_(3+x)V_(2) O_7(OH)_(2)·2_H2 O nanoflakes exhibited high Zn^(2+) diffusion coefficient,smaller charge-transfer resistance and good reversibility of Zn^(2+) intercalation/de-intercalation,thus leading to superior electrochemical performance.While in ZnS04 aqueous electrolyte,the cathode material cannot sufficiently transform into Zn_(3+x)V_(2) O_7(OH)_(2)·2 H_(2) O thereby corresponding to inferior electrochemical behaviors.Underlying mechanism and influencing factors of such a transformation phenomenon was also explored.This work not only reports a high-performance ZIB cathode material based on electrochemically induced transformation of vanadium oxides,but also provides new insights into Zn^(2+)-storage electrochemistry.展开更多
Rechargeable aqueous zinc-ion batteries are promising candidate for gridscale energy storage.However,the development of zinc-ion batteries has been plagued by the lack of cathode materials with high specific capacity ...Rechargeable aqueous zinc-ion batteries are promising candidate for gridscale energy storage.However,the development of zinc-ion batteries has been plagued by the lack of cathode materials with high specific capacity and superior lifespan.Herein,hexagonal Cs_(0.3)V_(2)O_(5)cathode is fabricated and investigated in zinc-ion batteries.Compared with the traditional vanadium oxides,the introduction of Cs changes the periodic atomic arrangements,which not only stabilizes the open framework structure but also facilitates the Zn^(2+)diffusion with a lower migration energy barrier.Consequently,high specific capacity of 543.8 mA h g^(-1)at 0.1 A g^(-1)is achieved,which surpasses most of reported cathode materials in zinc-ion batteries.The excellent cycle life is achieved over 1000 cycles with about 87.8%capacity retention at 2 A g^(-1).Furthermore,the morphological evolution and energy storage mechanisms are also revealed via a series of techniques.This work opens up a phase engineering strategy to fabricate the hexagonal vanadium oxide and elucidate the application of phase-dependent cathodes in zinc-ion batteries.展开更多
A mode-locked erbium doped fiber laser（EDFL） is demonstrated using the vanadium oxide（V2O5） material as a saturable absorber（SA）. The V2O5 based SA is hosted into poly ethylene oxide film and attached on fiber f...A mode-locked erbium doped fiber laser（EDFL） is demonstrated using the vanadium oxide（V2O5） material as a saturable absorber（SA）. The V2O5 based SA is hosted into poly ethylene oxide film and attached on fiber ferule in the laser cavity. It shows 7% modulation depth with 71 MW/cm2 saturation intensity. By incorporating the SA inside the EDFL cavity with managed intra-cavity dispersion, ultrashort soliton pulses are successfully generated with a full width at half maximum of 3.14 ps. The laser operated at central wavelength of 1559.25 nm and repetition frequency of 1 MHz.展开更多
We investigate the resistive switching characteristics of a Cu/VOx/W structure. The VOx film is deposited by radio- frequency magnetron sputtering on the Cu electrode as a dielectric layer. The prepared VOx sample str...We investigate the resistive switching characteristics of a Cu/VOx/W structure. The VOx film is deposited by radio- frequency magnetron sputtering on the Cu electrode as a dielectric layer. The prepared VOx sample structure shows reproducible bipolar resistive switching characteristics with ultra-low switching voltage and good cycling endurance. A modified physical model is proposed to elucidate the typical switching behavior of the vanadium oxide-based resistive switching memory with a sudden resistance transition, and the self-saturation of reset current as a function of compliance current is observed in the test, which is attributed to the conducting mechanism is discussed in detail. growth pattern of the conducting filaments. Additionally, the related展开更多
Vanadium oxides,par-ticularly hydrated forms like V_(2)O_(5)·nH_(2)O(VOH),stand out as promising cathode candidates for aqueous zinc ion batteries due to their adjustable layered structure,unique electronic chara...Vanadium oxides,par-ticularly hydrated forms like V_(2)O_(5)·nH_(2)O(VOH),stand out as promising cathode candidates for aqueous zinc ion batteries due to their adjustable layered structure,unique electronic characteristics,and high theoretical capacities.However,challenges such as vanadium dissolution,sluggish Zn^(2+)diffusion kinetics,and low operating voltage still hinder their direct application.In this study,we present a novel vanadium oxide([C_(6)H_(6)N(CH_(3))_(3)]_(1.08)V_(8)O_(20)·0.06H_(2)O,TMPA-VOH),developed by pre-inserting trimethylphenylammonium(TMPA+)cations into VOH.The incorporation of weakly polarized organic cations capitalizes on both ionic pre-intercalation and molecular pre-intercalation effects,resulting in a phase and morphology transition,an expansion of the interlayer distance,extrusion of weakly bonded interlayer water,and a substantial increase in V^(4+)content.These modifications synergistically reduce the electrostatic interactions between Zn^(2+)and the V-O lattice,enhancing structural stability and reaction kinetics during cycling.As a result,TMPA-VOH achieves an elevated open circuit voltage and operation voltage,exhibits a large specific capacity(451 mAh g^(-1)at 0.1 A g^(-1))coupled with high energy efficiency(89%),the significantly-reduced battery polarization,and outstanding rate capability and cycling stability.The concept introduced in this study holds great promise for the development of high-performance oxide-based energy storage materials.展开更多
A new layered mixed valence vanadium oxide, [CH 3NH 3] 2[(V ⅣO) 2(V ⅤO 4) 2], which contains interlamellar organic cations was prepared under hydrothermal conditions and its single crystal structure was determined. ...A new layered mixed valence vanadium oxide, [CH 3NH 3] 2[(V ⅣO) 2(V ⅤO 4) 2], which contains interlamellar organic cations was prepared under hydrothermal conditions and its single crystal structure was determined. It crystallizes in a triclinic system with space group P 1, a =0 625 59(8) nm, b =0 639 84(9) nm, c =0 747 19(10) nm, α =78 718(2)°, β =80 099(2)°, γ =77 100(2). The compound contains mixed valence V 4+ /V 5+ vanadium oxide layers constructed from VO 4 tetrahedra, pairs of edge sharing VO 5 square pyramid and methylamine with protonated organic amines occupying the interlayer space.展开更多
The development of aqueous zinc ion battery cathode materials with high capacity and high magnification is still a challenge.Herein,porous vanadium oxide/carbon(p-VO_(x)@C,mainly VO_(2) with a small amount of V_(2)O_(...The development of aqueous zinc ion battery cathode materials with high capacity and high magnification is still a challenge.Herein,porous vanadium oxide/carbon(p-VO_(x)@C,mainly VO_(2) with a small amount of V_(2)O_(3)) core/shell microspheres with oxygen vacancies are facilely fabricated by using a vanadium-based metal-organic framework(MIL-100(V)) as a sacrificial template.This unique structure can improve the conductivity of the VO_(x),accelerate electrolyte diffusion,and suppress structural collapse during circulation.Subsequently,H_(2)O molecules are introduced into the interlayer of VO_(x) through a highly efficient in-situ electrochemical activation process,facilitating the intercalation and diffusion of zinc ions.After the activation,an optimal sample exhibits a high specific capacity of 464.3 mA h g^(-1) at0.2 A g^(-1) and 395.2 mA h g^(-1) at 10 A g^(-1),indicating excellent rate performance.Moreover,the optimal sample maintains a capacity retention of about 89.3% after 2500 cycles at 10 A g^(-1).Density functional theory calculation demonstrates that the presence of oxygen vacancies and intercalated water molecules can significantly reduce the diffusion barrier for zinc ions.In addition,it is proved that the storage of zinc ions in the cathode is achieved by reversible intercalation/extraction during the charge and discharge process through various ex-situ analysis technologies.This work demonstrates that the p-VO_(x)@C has great potential for applications in aqueous ZIBs after electrochemical activation.展开更多
Zinc-ion batteries(ZIBs),in particular quasi-solid-state ZIBs,occupy a crucial position in the field of energy storage devices owing to the superiorities of abundant zinc reserve,low cost,high safety and high theoreti...Zinc-ion batteries(ZIBs),in particular quasi-solid-state ZIBs,occupy a crucial position in the field of energy storage devices owing to the superiorities of abundant zinc reserve,low cost,high safety and high theoretical capacity of zinc anode.However,as divalent Zn^(2+)ions experience strong electrostatic interactions when intercalating into the cathode materials,which poses challenges to the structural stability and higher demand in Zn^(2+)ions diffusion kinetics of the cathode materials.Here,a microwave-assisted hydrothermal method is adopted to prepare pre-potassiated hydrated vanadium pentoxide(K_(0.52)V_(2)O_(5)·0.29H_(2)O,abbreviated as KHVO)cathode material,in which the potassium ions preinserted into the interlayers can act as“pillars”to stabilize the lamellar structure,and crystal water can act as“lubricant”to improve the diffusion efficiency of Zn^(2+)ions.Consequently,the KHVO displays high electrochemical properties with high capacity(∼300 mAh/g),superior rate capability(69 mAh/g at 5 A/g)and ultralong cycling performance(>1500 cycles at 2 A/g)in quasi-solid-state ZIBs.These superior Zn storage properties result from the large diffusion coefficient and highly stable and reversible Zn^(2+)(de)intercalation reaction of KHVO.展开更多
Exploring suitable high-capacity V_(2)O_(5)-based cathode materials is essential for the rapid advancement of aqueous zinc ion batteries(ZIBs).However,the typical problem of slow Zn^(2+)diffusion kinetics has severely...Exploring suitable high-capacity V_(2)O_(5)-based cathode materials is essential for the rapid advancement of aqueous zinc ion batteries(ZIBs).However,the typical problem of slow Zn^(2+)diffusion kinetics has severely limited the feasibility of such materials.In this work,unique hydrated vanadates(CaVO,BaVO)were obtained by intercalation of Ca^(2+)or Ba^(2+)into hydrated vanadium pentoxide.In the CaVO//Zn and BaVO//Zn batteries systems,the former delivered up to a 489.8 mAh g^(-1)discharge specific capacity at 0.1 A g^(-1).Moreover,the remarkable energy density of 370.07 Wh kg^(-1)and favorable cycling stability yard outperform BaVO,pure V_(2)O_(5),and many reported cathodes of similar ionic intercalation compounds.In addition,pseudocapacitance analysis,galvanostatic intermittent titration(GITT)tests,and Trasatti analysis revealed the high capacitance contribution and Zn^(2+)diffusion coefficient of CaVO,while an in-depth investigation based on EIS elucidated the reasons for the better electrochemical performance of CaVO.Notably,ex-situ XRD,XPS,and TEM tests further demonstrated the Zn^(2+)insertion/extraction and Zn-storage mechanism that occurred during the cycle in the CaVO//Zn battery system.This work provides new insights into the intercalation of similar divalent cations in vanadium oxides and offers new solutions for designing cathodes for high-capacity aqueous ZIBs.展开更多
Graphene is a type of promising electrode material for high-energy and high-power density supercapacitors,but its electrochemical performance is greatly limited by the restacking problem.In this work,we reported a fac...Graphene is a type of promising electrode material for high-energy and high-power density supercapacitors,but its electrochemical performance is greatly limited by the restacking problem.In this work,we reported a facile approach to synthesis graphene with chemically bonded vanadium oxide(VOx)nanoparticles and demonstrated that chemically-bonded VOxnanoparticles can effectively prevent the graphene sheets from restacking and hence improve the electrochemical performance.The capacitance of VOxbonded graphene increases to 272 F/g compared to 183 F/g of pristine graphene in 1 M H3PO4 aqueous electrolyte at 2 A/g.The VOx-bonded graphene also showed improved rate capability in both H3PO4 and ionic liquid electrolytes.The capacitance retention increases to 54.5%from 28.5%at 100 A/g(compare to2 A/g)in H3PO4 and increases to 65.1%from 46.3%at 2 A/g(compare to 0.2 A/g)in neat ionic liquid.A high energy density of 84.4 Wh/kg is obtained within the voltage window of 4 V in ionic liquid.Even at a high-power density of 1000 W/kg,the VOx-bonded graphene shows a high energy density of 47.3 Wh/kg.展开更多
基金financially supported by the Science and Technology Research Program of Chongqing Municipal Education Commission(No.KJQN202300759)the Vanadium Titanium Materials Engineering Technology Research Center Foundation Project of Sichuan(No.2022FTGC07)+5 种基金the National Key R&D Program of China(No.2023YFC3009500)the National Natural Science Foundation of China(No.22379103)the Science and Technology Projects of Suzhou City(No.SYC2022043)the Campus Science Fund Project of Chongqing Jiaotong University(Nos.2020020086 and 2020023032)the Graduate Tutor Team Construction Project of Chongqing(No.JDDSTD2022006)the Graduate Student Research Innovation Project of Chongqing(No.2024S0110)
文摘The issue of water molecule activity in aqueous zinc-ion batteries presents a significant challenge.During the charging and discharging process,the strong polarity of water molecules tends to cause the dissolution of cathode materials,which reduces the cycle stability and specific capacity,consequently limiting the practical application of zinc-ion batteries.In this work,hydroxypropylβ-cyclodextrin(HP-β-CD),a special stereo cyclic organic molecule with hydrophobic inner cavity and hydrophilic outer cavity,is used as the intercalator for hydrated vanadium oxide(VOH)to enlarge the layer spacing and enhance the hydrophobicity of the cathode material.The larger interlayer spacing(13.9Å)of HP-β-CD-VOH is beneficial for improving ion mobility and the intrinsic electrochemical reaction kinetics.HP-β-CD-VOH delivers a discharge capacity of 336.7 mAh g^(-1)at 0.2 A g^(-1)and high-rate capability(242 mAh g^(-1)at 5 A g^(-1)).Due to the hydrophobic property of HP-β-CD in the interlayer pillar,the vanadium dissolution effect of polar water molecules can be reduced during charge and discharge;HP-β-CDVOH demonstrates sustained high efficiency and extended cycle longevity,maintaining a remarkable durability of 6000 cycles at a current density of 10 A g^(-1).This study presents an effective strategy for developing high-performance aqueous zinc-ion battery cathode materials.
基金National Natural Science Foundation of China(No.61376017)。
文摘Vanadium oxide(VO_(x))has garnered significant attention in the realm of resistive random-access memory(RRAM)owing to its outstanding resistive switching characteristics.However,the ambiguous mechanisms of resistive switching and inferior stability hinder its practical applications.Herein,an RRAM named VO_(x)/TiO_(2)/n^(++)Si device is prepared.It displays bipolar resistive switching behavior and shows superior cycle endurance(>200),a significantly high on/off ratio(>10^(2))and long-term stability.The tremendous improvement in the stability of the VO_(x)/TiO_(2)/n^(++)Si device compared with the Cu/VOx/n^(++)Si device is due to the p-i-n structure of VO_(x)/TiO_(2)/n^(++)Si.The switching mechanism of the VO_(x)/TiO_(2)/n^(++)Si device is attributed to the growth and annihilation of Cu conductive filaments.
基金financially supported by the National Natural Science Foundation of China(NSFC)(22171030 and 21771028)。
文摘Ni-ion aqueous batteries(NIBs)were considered an important development direction for aqueous batteries due to the high theoretical capacity(913 mA h g^(-1))and volume capacity(8136 mA h cm^(-3))of nickel metal.Herein,an electrolyte additive(dodecyl trimethyl ammonium chloride,DTAC)was used to improve the electrolyte environment,achieve efficient transport of Ni-ion,and combine the intercalated vanadium oxide cathodes to realize novel strategy NIBs.Firstly,the introduction of trace amounts of DTAC improved the high-concentration NiCl_(2)(4.2 M)electrolyte environment and reconstructed the hydrogen bond network.Molecular dynamics(MD)calculations and electrochemical results indicated that DTAC contributed to the desolvation process of Ni^(2+)and the realization of fast dynamics.The results of Ni symmetric cells demonstrated that DTAC enhanced the rapid migration of Ni-ion and achieved longer cycling stability(1750/1500 h at 0.2/0.5 mA cm^(-2)without obvious short circuits).Secondly,the insertion of organic small molecules(pyrrolidine)into vanadium oxide(V_(2)O_(5))to expand the interlayer spacing promoted the Ni-ion storage capacity of the cathodes.The capacity retention rate of Ni full battery after 6000 cycles at 5 A g^(-1)reached 82.17%.This work provided a novel strategy for the development of Ni-ion aqueous batteries.
基金supported by the National Natural Science Foundation of China(No.22179109).
文摘Although the enhancement of the zinc storage performance of layered vanadium oxides can be realized by the ionic pre-intercalation strategy,it also occupies a large number of active sites and thus fails to release the full potential of vanadium oxides.Here,vanadium oxide nanobelts with sodium-poor and oxygen defect-rich were constructed by regulating the content of pre-embedded sodium ions to strike a balance between pre-embedded ions and structural stability.The introduction of trace sodium ions not only increases the spacing of vanadium oxide layers but also occupies as few active sites as possible,which provides the possibility of massive storage,rapid diffusion and stabilization of the host structure for zinc ions.Moreover,the abundant oxygen defects transform the ion transport pathway from two-dimensional to three-dimensional,which greatly improves the ion transport rate in the host phase.Due to these advantages,the synthesized vanadium oxide nanobelts exhibit remarkable electrochemical properties,and this work provides a new idea for the design of structurally stable layered vanadium oxides with excellent properties.
基金funded by the Startup fund at Hubei University of Technology(Grant Nos.00709)a High-level Talent grant(Grant No.GCC2024012)from Hubei province.
文摘Pre-intercalation is the mainstream approach to inhibit the unpredicted structural degradation and the sluggish kinetics of Zn-ions migrating in vanadium oxide cathode of aqueous zinc-ion batteries(AZIBs),which has been extensively explored over the past 5 years.The functional principles behind the improvement are widely discussed but have been limited to the enlargement of interspace between VO layers.As the different types of ions could change the properties of vanadium oxides in various ways,the review starts with a comprehensive overview of pre-intercalated vanadium oxide cathode with different types of molecules and ions,such as metal ions,water molecules,and non-metallic cations,along with their functional principles and resulting performance.Furthermore,the pre-intercalated vanadium cathodes reported so far are summarized,comparing their interlayer space,capacity,cycling rate,and capacity retention after long cycling.A discussion of the relationship between the interspace and the performance is provided.The widest interspaces could result in the decay of the cycling stability.Based on the data,the optimal interspace is likely to be around 12?indicating that precise control of the interspace is a useful method.However,more consideration is required regarding the other impacts of pre-intercalated ions on vanadium oxide.It is hoped that this review can inspire further understanding of pre-intercalated vanadium oxide cathodes,paving a new pathway to the development of advanced vanadium oxide cathodes with better cycling stability and larger energy density.
基金supported by the National Natural Science Foundation of China (20803093,20833011,20525621)the Doctor Select Foundation for the University of State Education Ministry (200804251016)+1 种基金the Beijing Outstanding Ph.D.Thesis Foundation (YB 20091141401)the Hi-Tech Research and Development Program (863) of China (SQ2009AA06Z3488052)
文摘The nanometer CeO2 powder was prepared by the method of microwave-assisted heating hydrolysis,and the nanometer CeO2-supported or ordinary CeO2-supported vanadia catalysts with different vanadium loadings(atomic ratios:100V/Ce=0.1,1,4,10,and 20) were prepared by an incipient-wetness impregnation method.Spectroscopic techniques(XRD,FT-IR,Raman and UV-Vis DRS) were utilized to characterize the structures of VOx/CeO2 catalysts.The results showed that the structures of CeO2-supported vanadium oxide catalysts de...
基金This research was supported by National Natural Science Foundation of China(51601073)Jiangsu Distinguished Professor Project(1064901601)+1 种基金Jiangsu Provincial Six Talent Peaks Project(1062991801)Jiangsu University of Science and Technology Research Start-Up Fund(1062921905).
文摘Rechargeable magnesium ion batteries are potential candidates to replace the lithium ion batteries due to their high volumetric energy density,dendrite free cycling,and low costs.In present work,we have critically reviewed the recent advances made in the field of cathode materials development to achieve the high reversible capacities and working potentials.In first part,carbon-based cathodes such as fluorinedoped graphene nanosheets and graphite fluoride(CF0.8)are discussed in terms of compatibilities of pos让ive electrode materials and electrolyte solutions for rechargeable magnesium-ion batteries.Whereas,the second part of this review focuses on crystal structure of vanadium oxide and its capability to accommodate the Mg^2+ions.Likewise,electrochemical performance of selected vanadium oxide based cathodes including VO2(B),FeVO4.0.9H2(X Mc)2.5+yVO9+δ,RFC/V2O5 and V2O5/Graphene composite,are discussed at different temperatures.To support the future research on magnesium ion batteries,particularly positive electrode material developments,several innovative research directions are proposed.
基金supported by the National Natural Science Foundation of China,NSFC(51772205,51772208)the General Program of Municipal Natural Science Foundation of Tianjin(17JCYBJC17000,17JCYBJC22700)。
文摘The emergency of high-power electrical appliances has put forward higher requirements for the power density of lithium-ion batteries.Vanadium oxides with large theoretical capacities and high operating voltages are considered as prospective alternatives for the cathode of a new generation of lithium-ion batteries.However,the poor rate and cycling performance caused by the sluggish electrons/lithium transportation,irreversible phase changes,vanadium dissolution and large volume changes during the repeated lithium intercalation/deintercalation hinder their commercial development.Several optimizing routes have been carried out and extensively explored to address these problems.Taking V_(2)O_(5),VO_(2)(B),V_(6)O_(13),and V_(2)O_(3)as examples,this article reviewed their crystal structures and lithium storage reactions.Besides,recent progress in modification methods for the electrochemical insufficiencies of vanadium oxides,including nanostructure,heterogeneous atom doping,composite and self-supported electrodes has been systematically summarized and finally,the challenges for the industrialization of vanadium oxide cathodes and their development opportunities are proposed.
基金This study was supported by the National Natural Science Foundation of China(Grant no.51932011,51972346,51802356,and 51872334)Innovation-Driven Project of Central South University(No.2020CX024).
文摘Aqueous Zn-ion batteries(ZIBs)hold great potential in large-scale energy storage systems due to the merits of low-cost and high safety.However,the unstable structure of cathode materials and sluggish(de)intercalation kinetics of Zn2+pose challenges for further development.Herein,highly reversible aqueous ZIBs are constructed with layered hydrated vanadium oxide as a cathode material.The electrochemical performances are further tested with the optimized electrolyte of 3M Zn(CF3SO3)2 and a cut-off voltage of 0.4 to 1.3 V,exhibiting a remarkable capacity of 290mAh g−1 at 0.5Ag−1,and long-term cycling stability at high current density.Furthermore,the Zn2+storage mechanism of V3O7⋅H2O is recognized as a highly reversible(de)intercalation process with good structural stability,implying the potential application in the field of large-scale energy storage.
基金the Shenyang University of Technology(QNPY202209-4)the Key R&D project of Liaoning Province of China(2020JH2/10300079)+2 种基金the“Liaoning BaiQianWan Talents Program”(2018921006)the Liaoning Revitalization Talents Program(XLYC1908034)the National Natural Science Foundation of China(21571132).
文摘Potassium-ion batteries(PIBs)have been considered as promising candidates in the post-lithium-ion battery era.Till now,a large number of materials have been used as electrode materials for PIBs,among which vanadium oxides exhibit great potentiality.Vanadium oxides can provide multiple electron transfers during electrochemical reactions because vanadium possesses a variety of oxidation states.Meanwhile,their relatively low cost and superior material,structural,and physicochemical properties endow them with strong competitiveness.Although some inspiring research results have been achieved,many issues and challenges remain to be further addressed.Herein,we systematically summarize the research progress of vanadium oxides for PIBs.Then,feasible improvement strategies for the material properties and electrochemical performance are introduced.Finally,the existing challenges and perspectives are discussed with a view to promoting the development of vanadium oxides and accelerating their practical applications.
基金financial support by the National Natural Science Foundation of China (52002149)the Shenzhen Technical Plan Project (JCYJ20160301154114273)Australian Research Council through the ARC Discovery projects (DP16010^(4)340 and DP170100436)。
文摘Rechargeable aqueous zinc-ion batteries(ZIBs) have become a research hotspot in recent years,due to their huge potential for high-energy,fast-rate,safe and low-cost energy storage.To realize good electrochemical properties of ZIBs,cathode materials with prominent Zn^(2+) storage capability are highly needed.Herein,we report a promising ZIB cathode material based on electrochemically induced transformation of vanadium oxides.Specifically,K_(2) V_6 O_(16)·1.5 H_(2) O nanofibers were synthesized through a simple stirring method at near room temperature and then used as cathode materials for ZIBs in different electrolytes.The cathode presented superior Zn^(2+) storage capability in Zn(OTf)_(2) aqueous electrolyte,including high capacity of 321 mAh/g,fast charge/discharge ability(96 mAh/g delivered in 35 s), high energy density of 235 Wh/kg and good cycling performance.Mechanism analysis evidenced that in Zn(OTf)_(2) electrolyte,Zn^(2+) intercalation in the first discharge process promoted K_(2) V_6 O_(16)·1.5 H_(2) O nanofibers to transform into Zn_(3+x)V_(2) O_7(OH)_(2)·2 H_(2) O nanoflakes,and the latter served as the Zn^(2+)-storage host in subsequent charge/discharge processes.Benefiting from open-framework crystal structure and sufficiently exposed surface,the Zn_(3+x)V_(2) O_7(OH)_(2)·2_H2 O nanoflakes exhibited high Zn^(2+) diffusion coefficient,smaller charge-transfer resistance and good reversibility of Zn^(2+) intercalation/de-intercalation,thus leading to superior electrochemical performance.While in ZnS04 aqueous electrolyte,the cathode material cannot sufficiently transform into Zn_(3+x)V_(2) O_7(OH)_(2)·2 H_(2) O thereby corresponding to inferior electrochemical behaviors.Underlying mechanism and influencing factors of such a transformation phenomenon was also explored.This work not only reports a high-performance ZIB cathode material based on electrochemically induced transformation of vanadium oxides,but also provides new insights into Zn^(2+)-storage electrochemistry.
基金financialy supported by the National Natural Science Foundation of China(Nos.22109140,21875221,and 22075223)Distinguished Young Scholars Innovation Team of Zhengzhou University(No.32320275)the Youth Talent Support Program of High-Level Talents Special Support Plan in Henan Province(ZYQR201810148)
文摘Rechargeable aqueous zinc-ion batteries are promising candidate for gridscale energy storage.However,the development of zinc-ion batteries has been plagued by the lack of cathode materials with high specific capacity and superior lifespan.Herein,hexagonal Cs_(0.3)V_(2)O_(5)cathode is fabricated and investigated in zinc-ion batteries.Compared with the traditional vanadium oxides,the introduction of Cs changes the periodic atomic arrangements,which not only stabilizes the open framework structure but also facilitates the Zn^(2+)diffusion with a lower migration energy barrier.Consequently,high specific capacity of 543.8 mA h g^(-1)at 0.1 A g^(-1)is achieved,which surpasses most of reported cathode materials in zinc-ion batteries.The excellent cycle life is achieved over 1000 cycles with about 87.8%capacity retention at 2 A g^(-1).Furthermore,the morphological evolution and energy storage mechanisms are also revealed via a series of techniques.This work opens up a phase engineering strategy to fabricate the hexagonal vanadium oxide and elucidate the application of phase-dependent cathodes in zinc-ion batteries.
文摘A mode-locked erbium doped fiber laser（EDFL） is demonstrated using the vanadium oxide（V2O5） material as a saturable absorber（SA）. The V2O5 based SA is hosted into poly ethylene oxide film and attached on fiber ferule in the laser cavity. It shows 7% modulation depth with 71 MW/cm2 saturation intensity. By incorporating the SA inside the EDFL cavity with managed intra-cavity dispersion, ultrashort soliton pulses are successfully generated with a full width at half maximum of 3.14 ps. The laser operated at central wavelength of 1559.25 nm and repetition frequency of 1 MHz.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61274113 and 11204212)the Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No. NCET-11-1064)+1 种基金the Natural Science Foundation of Tianjin City, China (Grant Nos. 10SYSYJC27700, 13JCYBJC15700, and 10ZCKFGX01200)the Science and Technology Development Funds of Universities and Colleges of Tianjin City, China (Grant No. 20100703)
文摘We investigate the resistive switching characteristics of a Cu/VOx/W structure. The VOx film is deposited by radio- frequency magnetron sputtering on the Cu electrode as a dielectric layer. The prepared VOx sample structure shows reproducible bipolar resistive switching characteristics with ultra-low switching voltage and good cycling endurance. A modified physical model is proposed to elucidate the typical switching behavior of the vanadium oxide-based resistive switching memory with a sudden resistance transition, and the self-saturation of reset current as a function of compliance current is observed in the test, which is attributed to the conducting mechanism is discussed in detail. growth pattern of the conducting filaments. Additionally, the related
基金This work was supported by the National Science Foundation(CBET-1803256)Dr.C.Liu acknowledges the support from National Natural Science Foundation of China(52102277)the Fundamental Research Funds for the Central Universities,conducted by Tongji University.
文摘Vanadium oxides,par-ticularly hydrated forms like V_(2)O_(5)·nH_(2)O(VOH),stand out as promising cathode candidates for aqueous zinc ion batteries due to their adjustable layered structure,unique electronic characteristics,and high theoretical capacities.However,challenges such as vanadium dissolution,sluggish Zn^(2+)diffusion kinetics,and low operating voltage still hinder their direct application.In this study,we present a novel vanadium oxide([C_(6)H_(6)N(CH_(3))_(3)]_(1.08)V_(8)O_(20)·0.06H_(2)O,TMPA-VOH),developed by pre-inserting trimethylphenylammonium(TMPA+)cations into VOH.The incorporation of weakly polarized organic cations capitalizes on both ionic pre-intercalation and molecular pre-intercalation effects,resulting in a phase and morphology transition,an expansion of the interlayer distance,extrusion of weakly bonded interlayer water,and a substantial increase in V^(4+)content.These modifications synergistically reduce the electrostatic interactions between Zn^(2+)and the V-O lattice,enhancing structural stability and reaction kinetics during cycling.As a result,TMPA-VOH achieves an elevated open circuit voltage and operation voltage,exhibits a large specific capacity(451 mAh g^(-1)at 0.1 A g^(-1))coupled with high energy efficiency(89%),the significantly-reduced battery polarization,and outstanding rate capability and cycling stability.The concept introduced in this study holds great promise for the development of high-performance oxide-based energy storage materials.
基金Supported by the National Natural Science Foundation of China(No.2 0 1710 10 )
文摘A new layered mixed valence vanadium oxide, [CH 3NH 3] 2[(V ⅣO) 2(V ⅤO 4) 2], which contains interlamellar organic cations was prepared under hydrothermal conditions and its single crystal structure was determined. It crystallizes in a triclinic system with space group P 1, a =0 625 59(8) nm, b =0 639 84(9) nm, c =0 747 19(10) nm, α =78 718(2)°, β =80 099(2)°, γ =77 100(2). The compound contains mixed valence V 4+ /V 5+ vanadium oxide layers constructed from VO 4 tetrahedra, pairs of edge sharing VO 5 square pyramid and methylamine with protonated organic amines occupying the interlayer space.
基金supported by the National Natural Science Foundation of China(Nos.92163118,51972234)。
文摘The development of aqueous zinc ion battery cathode materials with high capacity and high magnification is still a challenge.Herein,porous vanadium oxide/carbon(p-VO_(x)@C,mainly VO_(2) with a small amount of V_(2)O_(3)) core/shell microspheres with oxygen vacancies are facilely fabricated by using a vanadium-based metal-organic framework(MIL-100(V)) as a sacrificial template.This unique structure can improve the conductivity of the VO_(x),accelerate electrolyte diffusion,and suppress structural collapse during circulation.Subsequently,H_(2)O molecules are introduced into the interlayer of VO_(x) through a highly efficient in-situ electrochemical activation process,facilitating the intercalation and diffusion of zinc ions.After the activation,an optimal sample exhibits a high specific capacity of 464.3 mA h g^(-1) at0.2 A g^(-1) and 395.2 mA h g^(-1) at 10 A g^(-1),indicating excellent rate performance.Moreover,the optimal sample maintains a capacity retention of about 89.3% after 2500 cycles at 10 A g^(-1).Density functional theory calculation demonstrates that the presence of oxygen vacancies and intercalated water molecules can significantly reduce the diffusion barrier for zinc ions.In addition,it is proved that the storage of zinc ions in the cathode is achieved by reversible intercalation/extraction during the charge and discharge process through various ex-situ analysis technologies.This work demonstrates that the p-VO_(x)@C has great potential for applications in aqueous ZIBs after electrochemical activation.
基金the National Natural Sci-ence Foundation of China(Nos.51972067,51802265,51802044,51902062 and 51802043)the Guangdong Natural Science Funds for Distinguished Young Scholar(No.2019B151502039).
文摘Zinc-ion batteries(ZIBs),in particular quasi-solid-state ZIBs,occupy a crucial position in the field of energy storage devices owing to the superiorities of abundant zinc reserve,low cost,high safety and high theoretical capacity of zinc anode.However,as divalent Zn^(2+)ions experience strong electrostatic interactions when intercalating into the cathode materials,which poses challenges to the structural stability and higher demand in Zn^(2+)ions diffusion kinetics of the cathode materials.Here,a microwave-assisted hydrothermal method is adopted to prepare pre-potassiated hydrated vanadium pentoxide(K_(0.52)V_(2)O_(5)·0.29H_(2)O,abbreviated as KHVO)cathode material,in which the potassium ions preinserted into the interlayers can act as“pillars”to stabilize the lamellar structure,and crystal water can act as“lubricant”to improve the diffusion efficiency of Zn^(2+)ions.Consequently,the KHVO displays high electrochemical properties with high capacity(∼300 mAh/g),superior rate capability(69 mAh/g at 5 A/g)and ultralong cycling performance(>1500 cycles at 2 A/g)in quasi-solid-state ZIBs.These superior Zn storage properties result from the large diffusion coefficient and highly stable and reversible Zn^(2+)(de)intercalation reaction of KHVO.
基金the financial support from the National Key Research and Development Program of China(2022YFA1207503)the Giga Force Electronics Interdisciplinary Funding(JJHXM002208-2023)。
文摘Exploring suitable high-capacity V_(2)O_(5)-based cathode materials is essential for the rapid advancement of aqueous zinc ion batteries(ZIBs).However,the typical problem of slow Zn^(2+)diffusion kinetics has severely limited the feasibility of such materials.In this work,unique hydrated vanadates(CaVO,BaVO)were obtained by intercalation of Ca^(2+)or Ba^(2+)into hydrated vanadium pentoxide.In the CaVO//Zn and BaVO//Zn batteries systems,the former delivered up to a 489.8 mAh g^(-1)discharge specific capacity at 0.1 A g^(-1).Moreover,the remarkable energy density of 370.07 Wh kg^(-1)and favorable cycling stability yard outperform BaVO,pure V_(2)O_(5),and many reported cathodes of similar ionic intercalation compounds.In addition,pseudocapacitance analysis,galvanostatic intermittent titration(GITT)tests,and Trasatti analysis revealed the high capacitance contribution and Zn^(2+)diffusion coefficient of CaVO,while an in-depth investigation based on EIS elucidated the reasons for the better electrochemical performance of CaVO.Notably,ex-situ XRD,XPS,and TEM tests further demonstrated the Zn^(2+)insertion/extraction and Zn-storage mechanism that occurred during the cycle in the CaVO//Zn battery system.This work provides new insights into the intercalation of similar divalent cations in vanadium oxides and offers new solutions for designing cathodes for high-capacity aqueous ZIBs.
基金supported by the Fundamental Research(Discipline Arrangement)Project funding from Shenzhen Science and Technology Innovation Committee(Grant no.JCYJ20170412154554048)the Peacock Team Project funding from Shenzhen Science and Technology Innovation Committee(Grant no.KQTD2015033110182370)+3 种基金the National Key Research and Development Project funding from the Ministry of Science and Technology of China(Grants nos.2016YFA0202400 and 2016YFA0202404)the Shenzhen Maker Project for Students(Grant no.GRCK2017042410565958)the Guangdong Innovation Team Project(no.2013N080)the Shenzhen Peacock Plan(Grant no.KYPT20141016105435850)。
文摘Graphene is a type of promising electrode material for high-energy and high-power density supercapacitors,but its electrochemical performance is greatly limited by the restacking problem.In this work,we reported a facile approach to synthesis graphene with chemically bonded vanadium oxide(VOx)nanoparticles and demonstrated that chemically-bonded VOxnanoparticles can effectively prevent the graphene sheets from restacking and hence improve the electrochemical performance.The capacitance of VOxbonded graphene increases to 272 F/g compared to 183 F/g of pristine graphene in 1 M H3PO4 aqueous electrolyte at 2 A/g.The VOx-bonded graphene also showed improved rate capability in both H3PO4 and ionic liquid electrolytes.The capacitance retention increases to 54.5%from 28.5%at 100 A/g(compare to2 A/g)in H3PO4 and increases to 65.1%from 46.3%at 2 A/g(compare to 0.2 A/g)in neat ionic liquid.A high energy density of 84.4 Wh/kg is obtained within the voltage window of 4 V in ionic liquid.Even at a high-power density of 1000 W/kg,the VOx-bonded graphene shows a high energy density of 47.3 Wh/kg.
