Academic literature on the topic 'Hybrid asymmetric pseudocapacitors'

Vanadium nitride (VN) shows promising electrochemical properties as an energy storage devices electrode, specifically in supercapacitors. However, the pseudocapacitive charge storage in aqueous electrolytes shows mediocre performance. Herein, we judiciously demonstrate an impressive pseudocapacitor performance by hybridizing VN nanowires with pseudocapacitive 2D-layered MoS2 nanosheets. Arising from the interfacial engineering and pseudocapacitive synergistic effect between the VN and MoS2, the areal capacitance of VN/MoS2 hybrid reaches 3187.30 mF cm−2, which is sevenfold higher than the pristine VN (447.28 mF cm−2) at a current density of 2.0 mA cm−2. In addition, an asymmetric pseudocapacitor assembled based on VN/MoS2 anode and TiN coated with MnO2 (TiN/MnO2) cathode achieves a remarkable volumetric capacitance of 4.52 F cm−3 and energy density of 2.24 mWh cm−3 at a current density of 6.0 mA cm−2. This work opens a new opportunity for the development of high-performance electrodes in unfavorable electrolytes towards designing high areal-capacitance electrode materials for supercapacitors and beyond.

Hierarchical NiCo₂O₄@NiMoO₄ core–shell nanowire/nanosheet arrays were successfully fabricated and assembled in an asymmetric supercapacitor device with outstanding electrochemical performance.

The advanced electrochemical properties, such as high energy density, fast charge–discharge rates, excellent cyclic stability, and specific capacitance, make supercapacitor a fascinating electronic device. During recent decades, a significant amount of research has been dedicated to enhancing the electrochemical performance of the supercapacitors through the development of novel electrode materials. In addition to highlighting the charge storage mechanism of the three main categories of supercapacitors, including the electric double-layer capacitors (EDLCs), pseudocapacitors, and the hybrid supercapacitors, this review describes the insights of the recent electrode materials (including, carbon-based materials, metal oxide/hydroxide-based materials, and conducting polymer-based materials, 2D materials). The nanocomposites offer larger SSA, shorter ion/electron diffusion paths, thus improving the specific capacitance of supercapacitors (SCs). Besides, the incorporation of the redox-active small molecules and bio-derived functional groups displayed a significant effect on the electrochemical properties of electrode materials. These advanced properties provide a vast range of potential for the electrode materials to be utilized in different applications such as in wearable/portable/electronic devices such as all-solid-state supercapacitors, transparent/flexible supercapacitors, and asymmetric hybrid supercapacitors.

Les supercondensateurs sont des systèmes de stockage de l’énergie destinés à des applications de nécessitant de fortes densité de puissance. Leur densité d’énergie peut être augmentée en développant de nouveaux matériaux d’électrode à forte capacitance. Dans cet objectif ces travaux décrivent le développement de matériaux composites à base de carbones nanostructurés (architectures avec des nanotubes de carbones et/ou de graphène oxydé réduit) et d’oxydes métalliques pseudocapacitifs (MnO2 et MoO3 pour les électrodes positive et négative respectivement). Les oxydes métalliques permettent de générer de fortes capacitances grâce à des réactions redox réversibles sur une large gamme de potentiels. La matrice carbonée nanostructurée induit une porosité et une conductivité des électrodes optimisées et assure le transport des ions et des électrons au sein des matériaux.L’électrode positive MnO2-rGO-CNTs est développée par pulvérisation des nanomatériaux carbonés directement sur le collecteur de courant avec un spray dynamique robotisé puis par croissance électrochimique de l’oxyde. Sa capacitance maximale est de 265 F/g. Dans une approche similaire, l’électrode négative MoO3-CNTs est développée, avec une capacitance maximale de 274 F/g. Les matériaux d’électrodes sont caractérisés par différentes techniques physicochimiques (microscopies, analyses de porosité, DRX, spectroscopies).Ces électrodes sont ensuite associées au sein d’un pseudocondensateur hybride asymétrique utilisant un électrolyte organique (LiTFSI/GBL) avec une tension de fonctionnement de 2V. Les performances de ce système en termes de densités d’énergie et de puissance ainsi que de stabilité électrochimique sont étudiées sur plusieurs milliers de cycles. La densité d’énergie maximale est calculée à 25 Wh/kg pour une densité de puissance de 0,1 kW/kg
Supercapacitors are energy storage devices for applications requiring high power densities. By developing new electrode materials with high capacitance energy densities can be enhanced. In that regard this work presents the development of composites materials associating nanostructured carbons (architectures with carbon nanotubes and/or reduced graphene oxide) and pseudocapacitive metal oxides (MnO2 and MoO3 for positive and negative electrodes respectively). Metal oxides generate high capacitances thanks to reversible redox reactions in a wide range of potentials. The nanostructured carbon matrix optimizes porosity and conductivity of the electrodes to ensure good ionic and electronic transport within the materials.First MnO2-rGO-CNTs is developed as a positive electrode using spray gun deposition of carbon nanomaterials before electrochemical growth of the oxide. The interest of these elaboration techniques lies in their easy large-scale implementation. Its maximum capacitance is measured at 265 F/g. In a similar approach MoO3-CNTs is developed as a negative electrode with a maximum capacitance of 274 F/g. The materials are characterized using different physicochemical methods (microscopy, spectroscopy, porosity analysis, XRD).These electrodes are then combined in an asymmetric hybrid pseudocapacitor in an organic electrolyte (LiTFSI/GBL) with an operating voltage window of 2V. The performances of this system in terms of energy and power densities as well as electrochemical stability were studied over several thousand cycles. The maximum energy density was found to be of 25 Wh/kg for a power density of 0.1 kW/kg