Hollow nanostructures of metal oxides as next generation electrode materials for supercapacitors

Abstract

Hollow nanostructures of copper oxides help to stabilize appreciably higher electrochemical characteristics than their solid counter parts of various morphologies. The specific capacitance values, calculated using cyclic voltammetry (CV) and charge-discharge (CD) studies, are found to be much higher than the values reported in literature for copper oxide particles showing intriguing morphologies or even composites with trendy systems like CNTs, rGO, graphene, etc. The proposed cost-effective synthesis route makes these materials industrially viable for application in alternative energy storage devices. The improved electrochemical response can be attributed to effective access to the higher number of redox sites that become available on the surface, as well as in the cavity of the hollow particles. The ion transport channels also facilitate efficient de-intercalation, which results in the enhancement of cyclability and Coulombic efficiency. The charge storage mechanism in copper oxide structures is also proposed in the paper.

V2O5 and its Carbon‐Based Nanocomposites for Supercapacitor Applications

“…Their channel‐like structure with interconnected mesopores and secondary micropores leads to maximum exposure to active surface and faster passage for diffusion of ion making them favorable for charging the electric double‐layer . However, irretrievable adsorption of large‐sized solvated ions generally minimizes the surface ion‐density, thereby limits the available active surface‐area on the carbon‐based EDLC electrodes . Moreover, these adsorbed‐ions catalyze the decomposition of these electrodes under high electric fields yielding collapsed structures with low surface area leading to lower energy and power densities that limits their commercial usage in energy storage devices ,…”

Performance of Na-ion Supercapacitors Under Non-ambient Conditions—From Temperature to Magnetic Field Dependent Variation in Specific Capacitance

“…The absorption bands at 1,009, 1,068, and 1,133 cm −1 , shown in the Figure S7a, could be assigned to the ν 3 type asymmetric stretching modes between P-O in PO 3− 4 . The ν 1 modes near 980 and 947 cm −1 are attributed to the PO 3− 4 intramolecular symmetric stretching vibrations (Sharma et al, 2018b). The asymmetric bending modes of the PO 3− 4 anion, assigned as v 4 , were observed at 629, 577, and 540 cm −1 (see Figure S7b).…”

“…It is now well established that, for useful electrochemically active materials, parameters such as: phase, particle morphology/size along with the nature of pores and pore-size/volume are critical (Singh and Chandra, 2015;Akhtar et al, 2016;Sharma et al, 2018b). The XRD plot obtained shown in Figure S1 could be indexed using the Pnmb space group of NaFePO 4 following the JCPDS card no.…”

“…It is clear that particles, with a cavity in the middle were stabilizing. Recently, hollow nanostructures of metal oxides have been suggested as electrode materials for next generation supercapacitors (Sharma et al, 2018b;Wei et al, 2018). Till date, there have been no reports, which have suggested formation of hollow NaFePO 4 particles/microspheres.…”

Electrodeposited Stable Binder‐Free Organic Ni(OH)2 Flexible Nanohybrid Electrodes for High‐Performance Supercapacitors

“…However, less abundance and expensive ruthenium have impeded the commercial use . On the other hand, relatively abundant and cheap transition metal oxides and hydroxides like NiO, TiO 2 , CuO, MnO 2 , Ni(OH) 2 , and Co(OH) 2 have gained attention due to their potential electrochemical properties. The use of Ni(OH) 2 has gained much attention due to their eco‐friendly compatibility, cheap and abundant resources .…”