Nickel-manganese structured and multiphase composites as electrodes for hybrid supercapacitors (original) (raw)
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Batteries
This study aims to quantify the synergistic effect of Ni2+ and Mn2+ ions on the capacitive performance of oxide, hydroxide and phosphate electrodes in alkaline electrolytes. Three types of phases containing both nickel and manganese in a ratio of one-to-one were selected due to their stability in alkaline media: oxides with ilmenite and spinel structures (NiMnO3 and Ni1.5Mn1.5O4); hydroxides with layered structures (β-Ni1/2Mn1/2(OH)2); and phosphates with olivine and maricite structures (LiNi1/2Mn1/2PO4 and NaNi1/2Mn1/2PO4). In the mixed hydroxides and phosphates, Ni2+ and Mn2+ ions randomly occupied one crystallographic site, whereas in the ilmenite oxide, a common face was shared by the Ni2+ and Mn4+ ions. The electrochemical parameters of the Ni–Mn compositions were evaluated in asymmetric hybrid supercapacitor cells working with alkaline electrolytes and activated carbon as a negative electrode. A comparative analysis of oxides, hydroxides and phosphates enabled us to differenti...
Ni–Mn hydroxides as new high power electrode materials for supercapacitor applications
Materials Letters, 2009
The coprecipitation of Ni and Mn hydroxides followed by freeze drying results in the formation of agglomerated 20-30 nm particles of complex hydroxide with spinel-like structure. The thermal decomposition of this hydroxide causes the formation of ilmenite-type complex oxide at T N 300°C without considerable changes in the Ni and Mn valence states according to X-ray photoelectron spectroscopy data. Further processing at T ≤ 400°C is accompanied by significant particle intergrowth though their internal structure remains nanostructured. Ni-Mn oxide-and hydroxide-based electrodes revealed a significant reversible electrochemical activity in the alkaline electrolytes and an extended operating voltage window (~1.8 V). Ni-Mn ilmenite-based electrode materials demonstrated a low fade rate and high specific electrochemical capacity values at high discharge rates (up to 70 mAh g − 1 at I = 70 mA cm − 2) that makes feasible their application in high rate batteries and electrochemical supercapacitors.
Ni(OH)2 and NiO Based Composites: Battery Type Electrode Materials for Hybrid Supercapacitor Devices
Materials, 2018
Nanocomposites of Ni(OH) 2 or NiO have successfully been used in electrodes in the last five years, but they have been falsely presented as pseudocapacitive electrodes for electrochemical capacitors and hybrid devices. Indeed, these nickel oxide or hydroxide electrodes are pure battery-type electrodes which store charges through faradaic processes as can be shown by cyclic voltammograms or constant current galvanostatic charge/discharge plots. Despite this misunderstanding, such electrodes can be of interest as positive electrodes in hybrid supercapacitors operating under KOH electrolyte, together with an activated carbon-negative electrode. This study indicates the requirements for the implementation of Ni(OH) 2-based electrodes in hybrid designs and the improvements that are necessary in order to increase the energy and power densities of such devices. Mass loading is the key parameter which must be above 10 mg•cm −2 to correctly evaluate the performance of Ni(OH) 2 or NiO-based nanocomposite electrodes and provide gravimetric capacity values. With such loadings, rate capability, capacity, cycling ability, energy and power densities can be accurately evaluated. Among the 80 papers analyzed in this study, there are indications that such nanocomposite electrode can successfully improve the performance of standard Ni(OH) 2 (+)//6 M KOH//activated carbon (−) hybrid supercapacitor.
Applied Sciences
MnO2 is the most favorable material in power storage due to its technological significance and potential applications in pseudocapacitance (due to various oxidative states allowing efficient charge transfer to meet energy demands), where its properties are considerably influenced by its structure and surface morphology. In the present study, a facile hydrothermal route was used to produce different phases of MnO2 (α, β, and γ) with different morphologies. The electrochemical performance of the synthesized phases was studied in aqueous sodium sulfate as an electrolyte. X-ray diffraction, UV–Vis spectroscopy, and Fourier-transform infrared spectroscopy were used to characterize the synthesized material. The surface morphology and topography were examined using field-emission scanning electron microscopy. The direct band gap of α-, β-, and γ-MnO2 was found to be 1.86 eV, 1.08 eV, and 1.68 eV, lying in the semiconducting range, further enhancing the electrochemical performance. It was f...
Journal of Materials Science: Materials in Electronics, 2016
problems [1]. It gives immense challenge to investigate high performance, low-cost and environmental friendly energy storage devices needed for modern civilization [1]. This can be achieved by clean energy sources and carriers, including hydrogen storage, lithium batteries and supercapacitors [2]. Amongst these, supercapacitors have attracted more attention due to their unique characteristics such as enormous power density, good reversibility, low maintenance cost, high cycling stability and environmental friendliness [3, 4]. Furthermore, supercapacitors ill the gap between conventional capacitors and secondary batteries. On the basis of energy storage mechanism supercapacitors are categorized into two groups: electric double layer capacitors (EDLCs) and pseudocapacitors. In EDLCs charges are stored by forming electric double layer of ions at the electrode-electrolyte interfaces while in pseudocapacitors charges are stored by redox reactions occurring on the surface of the electrode [5]. Carbon based materials like activated carbons, carbon nanotubes and graphene belong to EDLC's and transition metal oxides/hydroxides as well as conductive polymers are pseudocapacitive [6]. The transition metal oxides provide superior electrochemical performance with high speciic capacitances and good electrochemical stability [7]. RuO 2 based supercapacitors show good electrochemical performance, but sufer from high material cost and toxicity [8]. Therefore its comprehensive production is not beneicial. Other low-cost transition metal oxides such as SnO 2 , MnO x , NiO, CuO x , Co 3 O 4 , Fe 2 O 3 , TiO 2 , MoO 2 , and VOx are considered as ideal electrode materials in electrochemical supercapacitors [9-11]. Mn 3 O 4 and NiO materials have been studied extensively due to their superior electrochemical performance in pseudocapacitor as compared with carbon based materials. Mn 3 O 4 and NiO electrodes show low speciic capacitance due to its poor electrical conductivity.
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.
Herein, we develop the first flexible, low-cost and high-performance hybrid electrode based on MnO2 and various levels of Ni doped MnO2 by employing a chemical precipitation method and characterized by various techniques. The X-ray diffraction patterns indexed to the tetragonal structure of α-MnO2. Morphological studies show the synthesized particles to be combined nanospherical with nanorod structure. Their capacitive behaviour was studied by cyclic voltammetry, galvanostatic charge-discharge studies and impedance analysis. Among the various level of doping the specific capacitance of the MnO2: Ni (0.075 M) exhibited a highest specific capacitance of 765 F/g than pure MnO2 (212 F/g).
Journal of Power Sources, 2007
Carbon-supported MnO 2 nanorods are synthesized using a microemulsion process and a manganese oxide/carbon (MnO 2 /C) composite is investigated for use in a supercapacitor. As shown by high-resolution transmission electron microscopy the 2 nm × 10 nm MnO 2 nanorods are uniformly dispersed on the carbon surface. Cyclic voltammograms recorded for the MnO 2 /C composite electrode display ideal capacitive behaviour between −0.1 and 0.8 V (vs. saturated calomel electrode) with high reversibility. The specific capacitance of the MnO 2 /C composite electrode found to be 165 F g −1 and is estimated to be as high as 458 F g −1 for the MnO 2 . Based on cyclic voltammetric life-cycle tests, the MnO 2 /C composite electrode gives a highly stable and reversible performance for up to 10,000 cycles.
Study and optimisation of manganese oxide-based electrodes for electrochemical supercapacitors
Journal of Power Sources, 2009
A manganese oxide material was synthesised by an easy precipitation method based on reduction of potassium permanganate(VII) with a manganese(II) salt. The material was treated at different temperatures to study the effect of thermal treatment on capacitive property. The best capacitive performance was obtained with the material treated at 200 • C. This material was used to prepare electrodes with different amounts of polymer binder, carbon black and graphite fibres to individuate the optimal composition that gave the best electrochemical performances. It was found that graphite fibres improve the electrochemical performance of electrodes. The highest specific capacitance (267 F g −1 MnO x ) was obtained with an electrode containing 70% of MnO x , 15% of carbon black, 10% of graphite fibres and 5% of PVDF. This electrode, with CB/GF ratio of 1.5, showed a higher utilization of manganese oxide. The results reported in the present paper further confirmed that manganese oxide is a very interesting material for supercapacitor application.
Composite electrodes for electrochemical supercapacitors
Journal of Applied Electrochemistry, 2009
Manganese dioxide nanofibers with length ranged from 0.1 to 1 lm and a diameter of about 4-6 nm were prepared by a chemical precipitation method. Composite electrodes for electrochemical supercapacitors were fabricated by impregnation of the manganese dioxide nanofibers and multiwalled carbon nanotubes (MWCNT) into porous Ni plaque current collectors. Obtained composite electrodes, containing 85% of manganese dioxide and 15 mass% of MWCNT, as a conductive additive, with total mass loading of 7-15 mg cm-2 , showed a capacitive behavior in 0.5-M Na 2 SO 4 solutions. The decrease in stirring time during precipitation of the nanofibers resulted in reduced agglomeration and higher specific capacitance (SC). The highest SC of 185 F g-1 was obtained at a scan rate of 2 mV s-1 for mass loading of 7 mg cm-2. The SC decreased with increasing scan rate and increasing electrode mass.