Transition Metal Oxide Materials Research Articles

Nickel-Copper Bimetallic Oxide Nanoparticles Prepared by Simple Coprecipitation Method as High Performance Electrode Materials for Asymmetric Supercapacitors.

Supercapacitors with transition bimetallic oxides as pseudocapacitive materials have been of wide concern for their excellent energy storage performance. In this work, a simple coprecipitation method was used to synthesize the precursor, followed by calcination to prepare Ni-Cu bimetallic oxide materials. The structure, morphology and properties of the materials prepared by different precipitating agents and different calcination temperatures of NCO-H2C2O4 precursor were investigated. The optimum precipitant was determined to be H2C2O4, and Ni-Cu nanoparticles with regular lamellar microstructure were obtained at the calcination temperature of 400 °C. The nanostructure and morphology provide a large active channel for the rapid diffusion of electrolyte ions, and the specific capacitance of NCO-H2C2O4-400 electrode material can reach 740.31 F/g Cs at 1 A/g. The investigation of charge storage mechanism shows that the contribution rate of capacitance and diffusion control is about 37.9% and 67.2%, respectively. The electrochemical test results of the asymmetric supercapacitors (ASC) constructed with NCO-H2C2O4-400 and activated carbon show that the specific capacitance, energy density, and power density of the capacitor are 52.66 F/g, 16.45 Wh/kg, and 759.51 W/kg, respectively. Even after 5000 charge/discharge cycles at 5 A/g, it can still keep 90.57% of its initial capacity. This work not only provides competitive electrode materials for energy storage devices but also provides a feasible strategy for producing complex transition metal oxide materials with high capacitance performance.

(Invited) How to Mitigate Excited State Polaron Formation in Transition Metal Oxide Photocatalysts

We measure how lattice versus electronic coupling in transition metal oxide photocatalysts can mitigate photoexcited polaron formation. Despite well-aligned energetics for photocatalysis, transition metal oxide materials have limited carrier mobilities due to the formation of polarons. The coupling of photoexcited charge carriers with phonons in the crystal lattice causes carrier localization and results in transport that relies on site-to-site hopping. Models that predict polaron formation are limited to ground-state predictions, which limits the exploration of new photocatalysts. Small polaron formation rates have been measured to be independent of defects, dopants, surface treatments, and other material tuning parameters. Our transient extreme ultraviolet (XUV) measurements show the first hints about how electronic correlations can be used to counter polaron formation for increased transport. For example, in CuFeO2, we add Cu layers between FeO6 octahedra, which increases photoexcited transport compared to α-Fe2O3. In ErFeO3, where Er frustrates FeO6 octahedra, coherent Fe-Fe charge hopping due to correlated electron interactions slows polaron formation. We frame our discussion in terms of the Hubbard-Holstein Hamiltonian, which we are slowly proving can be used to guide materials design rules for non-polaronic photocatalysts using only ground-state DFT parameters.

Effect of Sm dopant on electrocatalytic activity of AgNbO3 perovskite fabricated by sonication method for Oxygen Evaluation Reaction (OER)

Excessive reliance on fossil fuels causes a variety of difficulties and the use of efficient electrocatalysts material has exhibited significant attention for high electrocatalytic activity. Most transition metal oxide materials performance can be enhanced by the incorporation of metals for OER activity. This work presents the synthesis of samarium (Sm) doped silver niobium oxide (AgNbO3) was achieved using sonication techniques. An electrocatalyst, Sm-doped AgNbO3, has shown promising results for oxygen evolution reaction (OER) in alkaline medium with a significant increase in active sites, enhanced electrical conductivity and improved stability. The Sm-doped AgNbO3 electrocatalyst exhibits overpotential of 203 mV and Tafel slope of 35.22 mV dec−1 for OER activity at current densities of 10 mA cm−2. By utilizing, electrochemical surface area (ECSA), the Sm-doped AgNbO3 electrocatalyst exhibited higher ECSA values of 1009 cm−2 with a higher roughness factor of 2008.60. Further, observations of low charge transfer resistance value (Rct = 0.17 Ω) along with a durability of 50 h, indicate that this material is highly efficient and long-lasting as an electrocatalyst for energy conversion systems.

Mn-doped V2O5@rGO towards high-performance electrode materials for aqueous zinc-ion supercapacitors

In order to address the diverse energy storage requirements, there is an urgent need to fabricate supercapacitors with high specific capacitance, long cycle life, high power density and high energy density. Among various transition metal oxide materials, vanadium pentoxide emerges as a promising candidate for cathode materials in supercapacitors. Herein, we report an ion intercalation strategy to synthesize Mn-doped V2O5 (MnVO) and recombine it with reduced graphene oxide (rGO) to form Mn-doped V2O5@rGO (MnVO@rGO) hybrids with special hierarchical structure. During the hydrothermal process, Mn2+ gradually inserts into the layer spacing of V2O5 to form nanobelts, which could be cross-linked with graphene nanosheets to form MnVO@rGO 3D skeleton network. This unique structure enables the MnVO@rGO electrode to exhibit excellent specific capacitance of 1120 F g−1 at 0.2 A g−1. Outstanding cycling performance is demonstrated by achieving a capacity retention rate of 91.5 % after 2000 cycle. The symmetrical supercapacitor device assembled with MnVO@rGO as both positive and negative electrodes exhibits an energy density of 150.75 and 77.5 W h Kg−1 at power density of 450 and 9000 W kg−1, respectively. Moreover, DFT calculations also have been employed to account for the improved electrochemical performances of MnVO@rGO. Besides, the excellent electrochemical performances of MnVO@rGO indicate that it has broad application prospects in future energy storage devices.

Facet-Dependent Interfacial Charge Transfer between T-Phase VS2 Nanoflakes and Rutile TiO2 Single Crystals.

The hybridizations of two-dimensional (2D) metallic materials with semiconducting transition metal oxides (TMOs) register attractive heterojunctions, which can find various applications in photostimulated circumstances. In this work, we developed an ambient-pressure chemical vapor deposition method to directly grow T-VS2 on atomically smooth rutile TiO2 single crystals with different terminations and thus successfully constructed a heterojunction model of VS2/TiO2 with a well-defined clean interface. Detailed measurements with Kelvin probe force microscopy revealed the facet-dependent charge transfer occurring at the VS2/TiO2 interfaces, seeing variations not only in the amount and direction of the transferred electrons but also in the photoinduced surface potential changes and the dynamics of photogenerated charge carriers under ultraviolet irradiation. Interestingly, ultrathin T-VS2 was found with considerable magnetism at room temperature, disregarding the charge exchange with the TiO2 substrates. These results may bring deep insights into the photoinspired functionalities of the hybridized system combining metallic transition metal dichalcogenides and TMO materials.

Synergistic RB5 dye degradation and oxygen evolution reaction (OER) catalysis by WO3 nano-pellets: mechanistic insights and water remediation applications

Transition metal oxides (TMO), a non-noble element based oxides, establish remarkable potential in the realm of textile wastewater remediation and water splitting due to their sustainable catalytic performance. Highly functional TMO materials, in form of nanostrcutures, are of great interest owing to their robust photo and electro-catalytic activities for instituting sustainable development for the water and energy resource management framework. In the present article, we have reported catalytically active WO3 nano-pellets (NP) synthesized using microwave-assisted for photocatalytic wastewater remediation and electrocatalytic oxygen evolution reaction (OER). Promisingly, WO3 NP abetted degradation of the reactive black 5 (RB5) dye by almost 95 % in short time interval of 60 min in exposer of sun light. Present work includes the strategies to remove and observe the progression of reaction kinetics of dye degradation in neutral and alkaline media. By varying concentration of the catalyst (ranging from 250 mg/L to 1000 mg/L, in the step of 250 mg/L), we have prolifically verified that 750 mg/L turn out optimal dosage for 100% degradation in time interval of 120 min. Besides, WO3 NP has shown highest photocatalytic behaviour at 9 pH. The WO3 NP shows the electrocatalytic OER performance in an alkaline condition (1M KOH) with an overpotential of 418 mV to generate the geometric current density of 10 mA/cm² and Tafel slope of 178 mV dec⁻¹. Owing to robust nature, WO3 NP shows the almost similar photocatalytic response for ten cycles dye degradation and demonstrates the stable electrochemical charge transport for OER at 10 mA/cm2 for 50 hours.

Preparation of transition metal oxide mixed graphene electrode materials and its application in supercapacitors

The increasing prevalence of wearable electronic devices in contemporary society has led to heightened expectations for energy storage devices. These expectations encompass not only high power density and energy density, but also robust stability and resistance to bending. Consequently, the design and development of supercapacitors with versatile functionalities has emerged as a prominent area of research. The electrode material, which is one of the elements that can have the biggest impact on the operation of supercapacitors, has been the subject of numerous scientific advancements over the years. One promising approach is the combination of transition metal oxide and graphene material composite. By conducting a comprehensive review of relevant literature, this study synthesizes preparation methods from multiple sources, integrates the benefits of multiple technologies to develop a novel preparation method utilizing ultrasonic shock and the two-step interface self-assembly method, and compares the physical and chemical properties of different transition metal oxide mixed graphene electrode materials and their application in supercapacitors. In conclusion, the preparation methods of transition metal oxide mixed graphene electrode materials typically control their microscopic morphology in order to support structure, agglomeration, and spalling reduction, thereby enhancing the specific capacitance and cycle stability of supercapacitors and achieving the desired result of increasing specific surface area and support structure.

"Fast-Charging" Anode Materials for Lithium-Ion Batteries from Perspective of Ion Diffusion in Crystal Structure.

"Fast-charging" lithium-ion batteries have gained a multitude of attention in recent years since they could be applied to energy storage areas like electric vehicles, grids, and subsea operations. Unfortunately, the excellent energy density could fail to sustain optimally while lithium-ion batteries are exposed to fast-charging conditions. In actuality, the crystal structure of electrode materials represents the critical factor for influencing the electrode performance. Accordingly, employing anode materials with low diffusion barrier could improve the "fast-charging" performance of the lithium-ion battery. In this Review, first, the "fast-charging" principle of lithium-ion battery and ion diffusion path in the crystal are briefly outlined. Next, the application prospects of "fast-charging" anode materials with various crystal structures are evaluated to search "fast-charging" anode materials with stable, safe, and long lifespan, solving the remaining challenges associated with high power and high safety. Finally, summarizing recent research advances for typical "fast-charging" anode materials, including preparation methods for advanced morphologies and the latest techniques for ameliorating performance. Furthermore, an outlook is given on the ongoing breakthroughs for "fast-charging" anode materials of lithium-ion batteries. Intercalated materials (niobium-based, carbon-based, titanium-based, vanadium-based) with favorable cycling stability are predominantly limited by undesired electronic conductivity and theoretical specific capacity. Accordingly, addressing the electrical conductivity of these materials constitutes an effective trend for realizing fast-charging. The conversion-type transition metal oxide and phosphorus-based materials with high theoretical specific capacity typically undergoes significant volume variation during charging and discharging. Consequently, alleviating the volume expansion could significantly fulfill the application of these materials in fast-charging batteries.

Crystal orientation regulation of spin-orbit torque efficiency and magnetization switching in SrRuO<sub>3</sub> thin films

Spintronic devices utilize the spin property of electrons for the storage, transmission, and processing of information, and they possess inherent advantages such as low power consumption and non-volatility, thus attracting widespread attention from both academia and industry. Spin-orbit torque (SOT) is an efficient method of manipulating magnetic moments through using electric current for writing, controlling the spin-orbit coupling (SOC) effect within materials to achieve the mutual conversion between charge current and spin current. Enhancing the efficiency of charge-spin conversion is a critical issue in the field of spintronics. Strontium ruthenate (SRO) in transition metal oxides (TMO) has attracted significant attention as a spin source material in SOT devices due to its large and tunable charge-to-spin conversion efficiency. However, current research on SOT control in SRO primarily focuses on utilizing substrate strain, with limited exploration of other control methods. Crystal orientation can produce various novel physical properties by affecting material symmetry and electronic structure, which is one of the important means to control the properties of TMO materials. Considering the close correlation between the SOT effect and electronic structure as well as surface states, crystal orientation is expected to affect SOT properties by adjusting the electronic band structure of TMO. This work investigates the effect of crystal orientation on the SOT performance of SrRuO<sub>3</sub> film and develops a novel approach for SOT control. The (111)-oriented SRO/CoPt heterostructures and SOT devices are prepared by using pulse laser deposition, magnetron sputtering, and micro-nano processing techniques. Through harmonic Hall voltage(HHV) measurements, we find that the SOT efficiency reaches 0.39, and the spin Hall conductivity attains 2.19×10<sup>5</sup><inline-formula><tex-math id="Z-20240522222523">\begin{document}$\hbar $\end{document}</tex-math><alternatives><graphic specific-use="online" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20240367_Z-20240522222523.jpg"/><graphic specific-use="print" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20240367_Z-20240522222523.png"/></alternatives></inline-formula>/2<i>e</i> Ω<sup>–1</sup>·m<sup>–1</sup>, which are 86% and 369% higher than those of the (001) orientation, respectively. Furthermore, current-driven perpendicular magnetization switching is achieved in SrRuO<sub>3</sub>(111) device at a low critical current density of 2.4×10<sup>10</sup> A/m<sup>2</sup>, which is 37% lower than that of the (001) orientation. These results demonstrate that the crystal orientation can serve as an effective approach to significantly enhancing the comprehensive performance of SrRuO<sub>3</sub>-based SOT devices, thus providing a new idea for developing high-efficiency spintronic devices.

Nonlinear optical properties in chiral copper oxide nanosheets.

Chiral transition metal oxides (TMOs) are in the forefront of research as potential active materials in various optoelectronic applications. However, the nonlinear optical (NLO) properties of the chiral TMOs have not been fully understood. Here, several kinds of copper oxide nanosheets capped with different chiral amino acids are synthesized. Notably, we investigate the NLO activities of these materials, including broadband second harmonic generation and transformation of nonlinear optical properties from saturable absorption to reverse saturable absorption. This work will broaden the use of chiral TMO materials in nonlinear photonic devices.

Submicron cubic ZnMn2O4 loaded on biomass porous carbon used as high-performance bifunctional electrode for lithium-ion and sodium-ion batteries

Due to their distinct electrochemical characteristics and large theoretical capacity, transition metal oxide materials have drawn a lot of attention. Transition metal oxides can be utilized as anode materials. However, their utilization is severely constrained by the volume expansion during charge and discharge. In this study, jute porous carbon was attached using submicron cubic ZnMn2O4. The unique three-dimensional structure of carbon gives the composite more strength and better cycle stability. The composite material still has a capacity of 1496.2 mA hg−1 after 200 cycles at the current density of 0.2 Ag−1 when used as a negative electrode material for lithium-ion batteries. Additionally, the composite, when used as a negative material for sodium-ion batteries, may still attain a capacity of 392.4 mA hg−1 after 200 cycles when the current density is 0.1 Ag−1.

Ferromagnetic ordering correlated strong metal–oxygen hybridization for superior oxygen reduction reaction activity

The efficiency of transition-metal oxide materials toward oxygen-related electrochemical reactions is classically controlled by metal-oxygen hybridization. Recently, the unique magnetic exchange interactions in transition-metal oxides are proposed to facilitate charge transfer and reduce activation barrier in electrochemical reactions. Such spin/magnetism-related effects offer a new and rich playground to engineer oxide electrocatalysts, but their connection with the classical metal-oxygen hybridization theory remains an open question. Here, using the MnxVyOz family as a platform, we show that ferromagnetic (FM) ordering is intrinsically correlated with the strong manganese (Mn)-oxygen (O) hybridization of Mn oxides, thus significantly increasing the oxygen reduction reaction (ORR) activity. We demonstrate that this enhanced Mn-O hybridization in FM Mn oxides is closely associated with the generation of active Mn sites on the oxide surface and obtaining favorable reaction thermodynamics under operating conditions. As a result, FM-Mn2V2O7 with a high degree of Mn-O hybridization achieves a record high ORR activity. Our work highlights the potential applications of magnetic oxide materials with strong metal-oxygen hybridization in energy devices.

Promoting Bifunctional Oxygen Catalyst Activity of Double-Perovskite-Type Cubic Nanocrystallites for Aqueous and Quasi-Solid-State Rechargeable Zinc-Air Batteries

Transition metal oxide materials are promising oxygen catalysts that are alternatives to expensive and precious metal-containing catalysts. Integration of transition metal oxides with high activity for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is an important pathway for good bifunctionality. In contrast to the conventional physical mixing and hybridization strategies, perovskite-type oxide provides an ideal structure for the integration of the transition metal element atoms on an atomic scale. Herein, B-site ordered double-perovskite-type La1.6Sr0.4MnCoO6 nanocrystallites with ultra-small cubic (20–50 nm) morphology and high specific surface areas (25 m2 g−1) were proposed. Rational designs were integrated to promote the ORR-OER catalysis, e.g., introducing oxygen vacancies via A-site cation substitution, further increasing surface oxygen vacancies via integration of a small amount of Pt/C and nanosizing of the material via a facile molten-salt method. The batteries with the La1.6Sr0.4MnCoO6 nanocrystallites and an aqueous alkaline electrolyte demonstrate decent discharge−charge voltage gaps of 0.75 and 1.10 V at 1 and 30 mA cm−2, respectively, and good cycling stability of 250 h (1500 cycles). A coin-type battery with a gel−polymer electrolyte also presents a good performance.

Fabrication of NiCo2O4@polyaniline heterostructure as positive electrode for asymmetrical supercapacitor

AbstractNiCo2O4, as a low‐cost and high‐performance binary transition metal oxide material, has been widely used in the fabrication of supercapacitor electrodes. However, the low energy density of binary metal oxides limits their large‐scale practical applications in supercapacitors, so it is highly desirable to design the structure of the NiCo2O4‐based supercapacitor. Therefore, in this paper, NiCo2O4 is compounded with polyaniline (PANI) to improve its electrochemical performance by exploiting the synergistic effect. The NiCo2O4@PANI composite electrode exhibits a specific capacitance of 561.2 F/g at 10 mV/s. In this study, asymmetric supercapacitors are assembled with NiCo2O4@PANI as the positive electrode and MXene as the negative electrode. The NiCo2O4@PANI‐CC//MXene‐CC supercapacitor has a specific capacitance of 31.95 F/g at a scan rate of 10 mV/s and a good cycle retention capacity of 86.2% after 3000 cycles. The excellent electrochemical performances are attributed to the dynamic equilibrium and fast redox kinetics of the two electrodes.

Solvation-enhanced electrolyte on layered oxide cathode tailoring even and stable CEI for durable sodium storage

Layered transition-metal oxide materials are ideal cathode candidates for sodium-ion batteries due to high specific energy, yet suffer severe interfacial instability and capacity fading owing to strongly nucleophilic surface. In this work, the interfacial stability of layered NaNi1/3Fe1/3Mn1/3O2 cathode was effectively enhanced by electrolyte optimization. And the interfacial chemistry between the cathode and four widely used electrolytes (EC/DMC, EC/EMC, EC/DEC and EC/PC) was elucidated through experiments and theoretical calculations. The Na+ solvation structures at cathode-electrolyte interface in all four electrolytes exhibited enhanced coordination due to high electron density and strong nucleophilicity of oxide surface, which promoted the electrolytes’ decomposition with decreased oxidation stability. Among them, the EC/DMC electrolyte showed the tightest solvation structure due to smaller molecular chains and stable electrochemistry, which derived an even and robust cathode electrolyte interphase. It effectively protected the cathode and facilitated the reversible Na+ transport during long cycles, enabling the batteries with a high capacity retention of 83.3% after 300 cycles. This work provides new insights into the role of electrode surface characteristics in interface chemistry that can guide the design of advanced electrode and electrolyte materials for rechargeable batteries.

Regulating electron distribution of P2-type layered oxide cathodes for practical sodium-ion batteries

For transition metal oxide materials, high Ni content is an effective method to obtain a high specific capacity. However, the theoretical capacity is determined due to the certain amount of variable charges of transition metal ions. The increased capacity in specific voltage window may attribute to the easier transport of alkali ions, instead of more active elements. Borrowing the theory of Ni-rich materials in LIB, excess Ni elements were added into P2-type layered oxide material to form the Jahn-Teller active Ni3+ ions. About 25%-61% Ni3+ ions can effectively promote de-/intercalation of Na+ ions due to the decreased diffusion energy barrier and increased adsorption energy of Na+. The preferred “Ni-rich” material Na0.67Mn0.45Ni0.22Co0.33O2 (Ni-R1) shows a reversible specific capacity of 114 mA h g−1 in the voltage range of 2.0–4.25 V. In addition, it shows an excellent cycle stability, the capacity retention ration is 80% after 1000 cycles at a current density of 1 A g−1. The in-depth study proves that, Jahn-Teller active Ni3+ ions can effectively regulate the valence electron distribution of surrounding ions in synthesis stage. However, it will promote Jahn-Teller distortion when the Ni3+ content is increased to 74%, which makes the rate performance deteriorate dramatically. The present work provides a simple and efficient way to increase the capacity in suitable voltage range for application.

A comparative study of the effect of synthesis method on the formation of P2- and P3-Na0.67Mn0.9Mg0.1O2 cathodes

Na-ion batteries offer a way to develop large-scale energy storage necessary for the increased adoption of renewable energy sources. Layered transition metal oxide materials for electrodes can be synthesised using abundant and non-toxic materials, decreasing costs and risks compared to lithium-ion batteries. Solid state processing is commonly used for synthesis, using long calcinations at high temperatures (>800 °C). Other synthetic routes, such as biotemplating, offer the opportunity to reduce reaction temperatures and times, and can enable access to different polymorphs. Here, we compare the properties of Na0.67Mn0.9Mg0.1O2 synthesised by both solid state and biotemplating, producing both P2 and P3 polymorphs to understand the differences which arise as a result of synthesis and temperature choice. We show that biotemplated P3-Na0.67Mn0.9Mg0.1O2 offers increased discharge capacity over the more commonly reported P2 phase for 50 cycles at C/5, 103 mAh g−1 for biotemplated P3-NMMO. Furthermore, the biotemplating samples demonstrate improved capacity after 50 cycles at C/5, and higher capacity delivered at 5C in both P2 and P3 phases over conventional solid state synthesis.

Dual modified NCMA cathode with enhanced interface stability enabled high-performance sulfide-based all-solid-state lithium battery

The severe interfacial side reactions between the sulfide-types electrolyte and layered transition metal oxides materials, especially for Ni-rich cathode, are regarded as one of the mainly detrimental factors, which limited the large-scale application of its in all-solid-state lithium batteries (ASSLBs). To effectively overcome aforementioned issues, here we design a core–shell structure LiNi0.88Co0.04Mn0.05Al0.03O2 (NCMA) with a Ni-poor surface, and then is coupled with LiNbO3 coating. This unique hierarchical structure not only significantly inhibits the decomposition of Li9.54Si1.74P1.4S11.7Cl0.3 (LSiPSCl) but also retards the degradation of NCMA cathode surface from layer to spinel or rock salt phase transformation, which greatly improves the interfacial stability of both them, thus promoting the enhancement of electrochemical performance of ALSSBs. The corresponding results demonstrate that the dual-modified NCMA with high mass loading of 35.6 mg cm−2 exhibit the improved capacity retention up to 96.4% after 300 cycles at 0.5C and good rate capability with the specific discharge capacity of 128.8 mAh g−1 at 2C at the temperature of 55 °C. This impactful modification strategy opens a new avenue for the application of Ni-rich cathode materials in high energy density sulfide-based ASSLBs.

Predicting the properties of NiO with density functional theory: Impact of exchange and correlation approximations and validation of the r2SCAN functional

Transition metal oxide materials are of great utility, with a diversity of topical applications ranging from catalysis to electronic devices. Because of their widespread importance in materials science, there is increasing interest in developing computational tools capable of reliable prediction of transition metal oxide phase behavior and properties. The workhorse of materials theory is density functional theory (DFT). Accordingly, we have investigated the impact of various correlation and exchange approximations on their ability to predict the properties of NiO using DFT. We have chosen NiO as a particularly challenging representative of transition metal oxides in general. In so doing, we have provided validation for the use of the r2SCAN density functional for predicting the materials properties of oxides. r2SCAN yields accurate structural properties of NiO and a local spin moment that notably persists under pressure, consistent with experiment. The outcome of our study is a pragmatic scheme for providing electronic structure data to enable the parameterization of interatomic potentials using state-of-the-art artificial intelligence (AI) and machine learning (ML) methodologies. The latter is essential to allow large scale molecular dynamics simulations of bulk and surface materials phase behavior and properties with ab initio accuracy.

One-Dimensional Layered Sodium Vanadate Nanobelts: A Potential Aspirant for High-Performance Supercapacitor Applications

The one-dimensional (1D) transition metal oxide (TMO) nanostructures have significant advantages in electrochemical energy storage fields. To date, simplifying the processing techniques and improving the yield without compromising the quality are one of the top priorities in pushing these TMO materials for scalable energy storage applications. This study presents a simple ultrasonic-assisted chemical route to prepare Na2V6O16 (NVO) nanobelts. The X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, and transmission electron microscopy characterizations are used to confirm the formation of 1D NVO nanobelt structures. The growth mechanism for the formation of NVO nanobelts is also provided. Moreover, these synthesized NVO nanobelts are used as an electrode material for supercapacitor (SC) applications, which exhibit a specific capacitance of 455 F g–1 at 0.5 A g–1 with typical capacitive behavior. An asymmetric coin cell SC device of activated carbon//NVO is also fabricated. This fabricated device delivers a high energy density of 42.4 W h kg–1 and a high power density of 4.3 kW h kg–1, along with 80% capacity retention after 5000 cycles. The 1D NVO nanobelt structures can be considered a promising cathode material with superior rate capability and high capacitance for SC applications.