V₂O₅ and its Carbon‐Based Nanocomposites for Supercapacitor Applications

Abstract

Vanadium pentoxide (V 2 O 5 ) is renowned among the highly efficient supercapacitor electrode-materials for high power and energy densities, excellent specific capacitance, prolonged cycle lives, variable oxidation states of V, reversible nature of interconversions, theoretical importance, etc. Various synthetic methodologies and morphologies, formation of composites, and doping for tuning properties are the additional causes of interest. Different synthetic techniques like sol-gel, solvothermal, electro-deposition, electro-spinning, atomic layer deposition, etc. are employed to prepare V 2 O 5 -based electrode materials with merits and demerits. High rate of material agglomeration and poor conductivity limit its usage in pristine morphology. Accordingly, the impact on charge storage behavior of V 2 O 5 on blending with various carbon-based systems has been explored for materials like activated carbons, conducting polymers, carbon nanotubes and functionalized graphene systems as binary/ternary composites. The aim has been to optimize the key factors such as reduced nanostructure lumping, minimal interfacial resistance and ultrafast charge diffusion across hollow porous structures which may eventually lead to the theoretically expected high specific capacitance (> 1000 F g À 1 ). In this review, we have discussed on the recent progress in the research of V 2 O 5 -based materials and highlighted on the correlation between morphology and electrochemical performances. In the course, we have attempted to delineate the advantage-disadvantages of different composite morphologies that may help to outline the present status and future aspects of these materials that the authors believe will be of first-hand assistance especially to the beginners in the field of research.

Carbon Transition‐metal Oxide Electrodes: Understanding the Role of Surface Engineering for High Energy Density Supercapacitors

“…[26] However, in-depth investigation about the construction of strongly coupled C-TMO hybrids with intimate interfacial contact is limited even though such factor may play a crucial role in the charge transfer process. Although substantial numbers of review articles are present on the development of supercapacitor, [5,[27][28][29][30][31][32][33][34] the present minireview focuses on recent development in the preparation of C-TMO hybrid material as efficient electrode towards high energy density SCs, which has not received due attention. Importantly, this report analyzes carbon materials as active support, core element, and conductive substrate in order to understand the specific roles of carbon and TMO.…”

On the Capacities of Freestanding Vanadium Pentoxide–Carbon Nanotube–Nanocellulose Paper Electrodes for Charge Storage Applications

“…[25,26] However, V 2 O 5 ⋅ nH 2 O electrodes generally exhibit low electronic conductivities and rapid capacity fading. [27,28] The latter capacity fading commonly stems from a combination of structural changes [29] and dissolution of vanadium in the electrolyte, especially, in aqueous electrolytes. [30] Many authors have, therefore, proposed possible solutions to the conductivity problem based on composite electrodes containing conducting polymers [31] or carbon additives, such as graphene, [32] carbon nanotubes (CNTs), [33] or carbon dots.…”

Electrochemically Generated γ‐LixV2O5 as Insertion Host for High‐Energy Li‐Ion Capacitors

“…Multiple oxidation states of Vanadium in V 2 O 5 (+2 to +5) facilitate the intercalation of more than one Li per formula unit . The calculated specific capacities of V 2 O 5 electrode for 1, 2, and 3 Li‐ion insertions are 147, 294, and 441 mAh g −1 , respectively . It is considered as a suitable host for reversible Li‐insertion/extraction due to the higher capacity values and layered crystal structure.…”

“…[36] The calculated specific capacities of V 2 O 5 electrode for 1, 2, and 3L i-ion insertions are 147, 294, and 441 mAh g À1 ,r espectively. [37] It is considered as as uitable host for reversible Li-insertion/extraction due to the higher capacity valuesa nd layered crystal structure. The crystal structure consists of weakly bondedl ayers with orthorhombic symmetry (pmnm space group), perpendicular to c-axis via van der Waals interactions and facilitating two dimensionalL i-ion migration pathways.…”