Spinel-Structured NiCo2O4 Nanorods as Energy Efficient Electrode for Supercapacitor and Lithium Ion Battery Applications (original) (raw)
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Facile solvothermal synthesis and high supercapacitor performance of NiCo2O4 nanorods
Journal of Alloys and Compounds, 2018
NiCo 2 O 4 nanorod arrays were synthesized employing a facile low-temperature solvothermal approach, followed by post-calcination treatment. The structural, morphological and elemental characterizations were done by diffraction, microscopic and spectroscopic techniques. The prepared sample was studied as an active electrode material for supercapacitor application in 2 M KOH aqueous electrolyte. The cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectral (EIS) studies were carried out to know the electrochemical activity of the prepared material. From the CV study, a high capacitance value of 440 F g À1 was obtained at a scan rate of 5 mV s À1 in a 3-electrode method. Apart from high capacitance value, the prepared electrode depicted 94% initial capacitance retention value after 2000 charge-discharge cycles at a current density of 8 A g À1. The fabricated symmetrical supercapacitor depicted a high energy density of 12.6 Wh kg À1 and a high power density of 4003 W kg À1. This was attributed to the better electrical conductivity of NiCo 2 O 4 nanorods.
In this work, NiCo 2 O 4 /O-g-C 3 N 4 nanocomposites (abbreviated as NCO/O-g-CN) have been synthesized using a multistep synthesis process. The transformations of g-C 3 N 4 to oxygenated g-C 3 N 4 during the synthesis of NiCo 2 O 4 /O-g-C 3 N 4 nanocomposites trigger electrochemical performances toward supercapacitor application. From the electrochemical study, the NCO/O-g-CN nanocomposite electrode was found to possess battery-type features and shows an outstanding specific capacity of 438.1 C/g at a current density of 1 A/g in a three-electrode system, which is higher than that of pristine NCO and g-CN. It has also gained excellent long-term cyclic stability performance, and its capacity retention was found to be 93.15% after 10 000 cycles at a current density of 4 A/g. The excellent performance of the NCO/ O-g-CN nanocomposite indicates synergistic effects of the individual materials toward the improved specific capacity performance. Furthermore, to evaluate the predominant mechanism followed by the NCO/O-g-CN nanocomposite, the Trasatti plot was used, and it was found to be 94.79% for the diffusion-controlled charge component and 5.20% for capacitive contribution. This finding shows that the NCO/O-g-CN nanocomposite can be used as a potential electrode material and might have promising applications in high-performance energy storage devices.
Journal of Energy Storage, 2021
In this study, we successfully synthesized NiCo 2 O 4 supported on Ni foam (NNCOs) with different morphologies by changing the synthesis conditions. The research results of electrochemical properties show that the morphologies have a strong influence on the electrochemical properties of materials. Specifically, the nanosheet-like NNCO-1 sample exhibited an enhanced specific capacity of 503.5 C g − 1 at current density of 1 A g − 1 , ca. 134-350 % higher than that of NNCO-2, NNCO-4 (nanorod-like) and NNCO-3 (grass-like). All materials also show high stability with the ability to maintain 95 to 97% capacitance after 2000 discharge cycles at a current density of 2 A g − 1. We hope that, the NNCO-1 material is promising electrode material for hybrid supercapacitor.
Materials
It is of great significance to design electrochemical energy conversion and storage materials with excellent performance to fulfill the growing energy demand. Bimetallic cobalt/nickel-based electrode materials exhibit excellent electrical conductivity compared to mono oxides. However, their potential as electrode materials for high-performance supercapacitors (SCs) is limited because of their poor cycling stability and high-capacity fading. This work demonstrates the synthesis of binder-free bimetallic NiCo2O4 nano-needles supported on CC (NCO@CC) via a facile and scalable hydrothermal process. Excellent electrical conductivity and interconnected nanostructure of NCO@CC nano-needles provide the fast transfer of electrons with numerous channels for ion diffusion. Owing to such features, the binder-free NCO@CC electrode for SC discloses excellent specific capacitance (1476 Fg−1 at 1.5 Ag−1) with 94.25% capacitance retention even after 5000 cycles. From these outstanding electrochemica...
Materials Today Energy, 2019
Nickel cobaltite is one of the most popular pseudocapacitance materials for creating high-performance energy-storage devices because of its low cost, high electric conductivity, excellent electrochemical properties, and environmental friendliness. In this study, nickel cobaltite with nanoneedle morphology was synthesized by adopting the hydrothermal method. Change in the nickel cobaltite from nanoneedle to nanoflake morphology was induced by a template of the surface of a self-assembly graphene oxide (GO)/multiwall carbon nanotube (MWCNT) three-dimensional block matrix. Electrodes fabricated from the nanoflake nickel cobaltite, GO, and MWCNT composite exhibited high specific capacitance of 1525 F g À1 at a current density of 1 A g À1 and 1081 F g À1 at a high current density of 100 A g À1. When these composite electrodes were used as both the anode and cathode to assemble a symmetric supercapacitor with a 6 M KOH electrolyte, the supercapacitor exhibited a maximum energy density of 25.2 Wh kg À1 and maximum power density of 5151 W kg À1. Moreover, it maintained an excellent cycling stability of 99.6% of the initial capacitance value after 7000 chargeedischarge cycles, demonstrating its remarkable potential for application in energy-storage and conversion devices.
NiCo 2 O 4 with oxygen vacancies as better performance electrode material for supercapacitor
In this paper, using a chemical reduction method, oxygen vacancies are introduced into different NiCo 2 O 4 nanostructures, crystal structure analyses and electrochemical property studies on oxygen vacancies are further described by two sets of in situ control experiments. Electrochemical data show that reduced NiCo 2 O 4 electrodes with appropriate oxygen vacancies exhibit a significant improvement on electrical conductivity and capacitance compared to the untreated electrodes. Interestingly, the capacitance of the reduced NiCo 2 O 4 nanosheets electrode (0.5-NiCo 2 O 4 NS-vac) and the reduced NiCo 2 O 4 nanowires electrode (0.5-NiCo 2 O 4 NW-vac) obtained from 0.5 M NaBH 4 solution is significantly higher than that of the pristine electrodes, and has increased by 77% and 100.4%, respectively. Due to the introducing of oxygen vacancies in NiCo 2 O 4 , part of CoeO and NieO bonds in the crystals are destroyed and the crystalline degree of the crystals decreases. However, the reduced NiCo 2 O 4 electrodes still maintain excellent cycling performance after cyclic test. These results indicate that the appropriate oxygen vacancies in NiCo 2 O 4 can be an efficient strategy for enhancing the performance of NiCo 2 O 4.
At present world facing major problems of rapid growth of population and global economy due to this demand for energy consumption has been considerably increased. Supercapacitor devices are emerging as one of the promising energy devices for the future energy technology. In this regards, the transition metal oxides are suitable electrode materials for pseudocapacitors due to different oxidation states and different ions. In this review article, we focused on the pure nickel oxide based materials synthesizing by various synthetic methods. Nowadays nickel oxide is emerging electrode material for energy storage application due to its thermal stability, high chemical stability, high theoretical specific capacity, low price, naturally abundant and environment friendliness. There are three important factors on which performance of supercapacitor mainly depends on namely electrochemical properties of the electrode material, electrolyte and voltage range. In this review paper, storage mechanism of supercapacitors with their types, characteristics of the electrode material, different synthesis methods of nickel oxide electrode material and different electrolyte materials have been reported.
Supercapacitors are one of the promising energy storage devices, which have been widely explored for energy storage applications owing to their unique characteristics like high power density, long cycle life (>100,000 cycles), and environmental friendliness. The electrode materials play a key role as the performance of supercapacitors is primarily depended on the types of the electrode materials. Therefore, it is imperative to explore new electrode materials that simultaneously exhibit a high-capacitance, high cycle life as well as high conductivity. Herein, we have successfully fabricated NiCo 2 O 4 @GO@PPy nanorods on flexible carbon cloth using a facile hydrothermal and electrodeposition method. The as-fabricated NiCo 2 O 4 @GO@PPy nanorods electrode present an excellent areal capacitance of 405 mF cm −2 at 1 mA cm −2 and outstanding capacitance retention of ∼78% after 5000 cycles at 10 A g-1. The improved electrochemical performance ascribed the complementary contributions of both componential structures in the hybrid electrode design.
Journal of Nanoscience and Nanotechnology, 2020
The widespread use of miniature electronic devices calls for energy-dense storage strategies. The supercapacitor-based energy storage devices with high areal capacitance are desired energy storage alternative. It is still a challenge to fabricate supercapacitor-based energy devices with consistent performance. The porous metal oxides with large areal capacitance are desired materials for electrode, but there exists a limited understanding of the influence of synthesis parameters on microstructural properties, which largely govern their electrochemical performance. In the present work, hierarchal spinel nickel cobaltite (NiCo 2 O 4) nanostructures were synthesized in the presence of the varying amount of hydrolyzing agent via a simple hydrothermal method coupled with a simple post-annealing process. This work focuses on understanding the influence of hydrolyzing agent in controlling the microstructure and hence ensuing electrochemical properties of the NiCo 2 O 4 based electrode. Based on the urea hydrolyzing content, the as synthesized NiCo 2 O 4 nanostructure varied from the rod, plate to nanoflower. The mesoporous nanostructures, with urea content 1.49 gm, exhibit a sizeable BJH surface area (79.2 m 2 g −1) and high mesopore volume (0.140 cm 3 g −1. Remarkably, the NiCo 2 O 4 nanoflower shows high specific capacitance of 3143.451 F/g at 2 mV/s scan rate, 1264.5 F/g at 1 A/g current density, energy density of 56 Wh/kg and power density of 8,400 W/kg in 3 M KOH electrolyte. The capacitance loss after 5000 cycles is 48% at the current density of 10 A/g, indicating their excellent cycling stability. The impressive electrocatalytic activity is largely ascribed to the high intrinsic electronic conductivity, superior mesoporous nanostructures and rich surface Ni active species of the NiCo 2 O 4 materials, which can largely boost the interfacial electroactive sites and charge transfer rates indicating promising applications as electrodes in future supercapacitors.