Vanadium Pentoxide with H₂O, K⁺, and Na⁺ Spacer between Layered Nanostructures for High‐Performance Symmetric Electrochemical Capacitors

Abstract

batteries and the power density similar to the electric double-layer capacitors. [1][2][3][4] Generally, the transition metal oxides and conducting polymers are used as the pseudocapacitor electrode materials, [3] since it stores electric charges based on the Faradaic and non-Faradaic reactions arising at the interface of electrode/electrolyte. [5] Several transition metal oxides, metal sulfides, and metal hydroxides have been displayed to be appropriate for the electrodes of supercapacitors. [6] Mostly, transition metal oxides (e.g., RuO 2 , MnO 2 , NiO, and V 2 O 5 ) are widely utilized as the electrode material to attain pseudocapacitive energy storage property due to their multivalence oxidation states. [7] Among the various metal oxides, vanadium pentoxide (V 2 O 5 ) is reflected to be the most capable candidate for pseudocapacitor owing to its natural abundance and existence of variable oxidation states from +2 to +5 (VO, V 2 O 3 , VO 2 , and V 2 O 5 ). [8] In addition, V 2 O 5 possess a higher theoretical capacitance value of ≈2120 F g −1 under a considerable potential window of 1 V, and this is recognized to the higher oxidation state of vanadium to transfer more than one electron instantly. [9,10] So, vanadium pentoxide nanostructures have been the most regarded materials in various applications, [11] such as batteries, [12][13][14] supercapacitors, [15,16] catalyst, [17] optical switching, [18] and energy-saving devices. [19] In supercapacitors, apart from the electrical/electrochemical properties, the specific capacitance of vanadium oxide also depends upon the morphology and synthesis techniques. [20] Recently, different types of nanostructured V 2 O 5 such as nanowires, [21] nanoribbons, [22] nanorods, [23] nanoplatelets, [24] and nanobelts [25] have been applied for supercapacitor electrodes. [26] Moreover, various synthetic methods such as hydrothermal/solvothermal, thermal decomposition, chemical vapor deposition, microwave-assisted synthesis, and sol-gel [27,28] methods have been adopted for the fabrication of different forms of vanadium oxide nanostructures. Among various synthesis techniques, the hydrothermal method is a low-cost, environmentally friendly, and widely used technique for the development of inorganic nanostructures. The hydrothermal method is a scalable and simple method, retaining autoclaves at lower operational temperatures with Vanadium oxide 2D layered nanostructures with the hydrous form of potassium (K + ) and sodium (Na + ) are synthesized via hydrothermal reaction between VOSO 4 · xH 2 O and different persulfate oxidants ((NH 4 ) 2 S 2 O 8 , K 2 S 2 O 8 , and Na 2 S 2 O 8 ). The physicochemical characterization suggests that the synthesized V 2 O 5 · 3H 2 O nanostructures possess layered morphology with considerable amount of water molecules accommodated between the interlayer spacing of nanostructures. Moreover, samples obtained using K 2 S 2 O 8 and Na 2 S 2 O 8 oxidants have K + (6.41%) and Na + (0.38%) ions intercalated on the 2D nanostructure along with the water mole...

Robust, Flexible, and Binder Free Highly Crystalline V2O5 Thin Film Electrodes and Their Superior Supercapacitor Performances

“…However, to meet the higher requirements of future systems, we need to improve their performance by designing new materials with high energy density and power density concurrently . There are several reports available on thin film energy storage devices (batteries and capacitors) for fulfilling the energy requirements to balance both power and energy on hybrid capacitors or asymmetric capacitors in both aqueous and organic electrolytes. − In typical asymmetric supercapacitors, pseudo capacitive (Faradaic) electrode materials have been used to improve energy storage performances.…”

Scalable Synthesis of Manganese-Doped Hydrated Vanadium Oxide as a Cathode Material for Aqueous Zinc-Metal Battery

“…31,35 A similar lattice vibrational mode in HVO-30 and MnHVO-30 is observed at 143 cm −1 . 40 Besides, other peaks located at 282, 404, 698, and 993 cm −1 match with that of the different vibrational modes of the cation inserted V 2 O 5 •nH 2 O. The FTIR data of all of the samples are compared in Figure 3c; the peak located in the range of 997− 1006 cm −1 originates from the characteristic V=O stretching vibration in the samples.…”

Synergistic integration of three‐dimensional architecture composed of two‐dimensional nanostructure ternary metal oxide for high‐performance hybrid supercapacitors

“…16,17 In general, the TMOs like MnO 2 , V 2 O 5 , MoO 3 , NiO, and Co 3 O 4 are featured with their excellent catalytic, electrical and electrochemical properties for electrochemical applications. [18][19][20][21] Among these TMOs, NiO and Co 3 O 4 are well-explored HSC electrode materials owing to their high theoretical capacitance and excellent batterytype Faradic electrochemical charge storage behavior. However, the practical applications of these mono-metal oxides are limited by their low electrical conductivity, limited electroactive sites, and poor cyclic stability.…”

“…Transition metal oxides (TMOs) are recognized as promising electrode materials for high‐energy HSCs 16,17 . In general, the TMOs like MnO 2 , V 2 O 5 , MoO 3 , NiO, and Co 3 O 4 are featured with their excellent catalytic, electrical and electrochemical properties for electrochemical applications 18‐21 . Among these TMOs, NiO and Co 3 O 4 are well‐explored HSC electrode materials owing to their high theoretical capacitance and excellent battery‐type Faradic electrochemical charge storage behavior.…”