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1.
In this work, cobalt from spent Li-ion batteries of cellular phones was recycled using electrochemical techniques. The efficiency,
structure and morphology of deposits were influenced by the pH solution and charge density. Maximum efficiency is obtained
for pH = 5.40 for all charge densities analyzed. The presence of the cobalt hcp phase for both pH solutions (5.40 and 2.70)
and charge density conditions (10.0 and 50.0 C cm −2) used in the electrodeposition process was detected by X-ray diffraction. The growth of the cobalt deposit is favored in
the crystallographic direction [002] for pH = 5.40 and in the direction [110] for pH = 2.70 when the charge density is 10.0 C cm −2. The [100] and [101] crystallographic directions of hcp phase were detected by X-ray diffractogram for both pH conditions
when the charge density was increased to 50.0 C cm −2. The potentiodynamic dissolution of the cobalt depends on its structural composition. 相似文献
2.
In this work the metallic cobalt was electrodeposited on 430 steel in order to obtain a low electrical resistance film made
to Co 3O 4. Pure cobalt was obtained by acidic dissolution of lithium cobalt oxide (LiCoO 2) present in exhausted Li-ion battery cathode. The electrodeposition was performed with a 96% efficiency at a potential of
1.50 V versus Ag/AgCl. The electrodeposited cobalt showed the face-centered cubic (23%) and hexagonal centered (77%) phases.
After oxidation at 850 °C for 1000 h in air, the cobalt layer was transformed into the Co 3O 4 phase. On the other hand, a sample without cobalt showed the usual Cr 2O 3 and FeCr 2O 4 phases. After 1000 h at 850 °C, in air the area specific resistance of the sample with the cobalt oxide layer was 0.038 Ω cm −2, while it was 1.30 Ω cm −2 for the bare sample. 相似文献
3.
Nanostructured Co 3O 4 was prepared via a simple two-step process: cathodic electrodeposition of cobalt hydroxide from additive free nitrate bath
and then heat treatment at 400 °C for 3 h. The prepared oxide product was characterized by powder X-ray diffraction, infrared
spectroscopy, surface area measurement, scanning electron microscopy, and transmission electron microscopy. Morphological
characterization showed that the oxide product was composed of porous nanoplates, and BET measurement displayed that the oxide
plates have the average pore diameter and the surface area of 4.75 nm and 208.5 m 2 g −1, respectively. The supercapacitive performance of the nanoplates was evaluated using cyclic voltammetry and charge–discharge
tests. A specific capacitance as high as 393.6 F g −1 at the constant current density of 1 A g −1 and an excellent capacity retention (96.5% after 500 charge–discharge cycles) was obtained. These results indicate that Co 3O 4 nanoplates can be recognized as high-performance electrode materials. 相似文献
4.
We demonstrate optimized supercapacitive characteristics of electrodeposited polyaniline by adding organic salt into electrolyte. The optimum amount of the organic salt is found to be 2 wt % which provides better ionic conductivity of the electrolyte, leading to the improved specific capacitance of 259 Fg ?1. This capacitance remains at up to 208 Fg ?1 (80% capacity retention) after 1000 charge–discharge cycles. The optimized organic salt added electrolyte causes better rate performance and higher cyclability. Significantly reduced electrochemical charge transfer resistance at the electrode/electrolyte interface results in the increased ionic conductivity, which can be useful in electrochemically preferred power devices for better applicability. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40306. 相似文献
5.
A composite electrode based on polyaniline (PANI) and hydrous RuO 2 is prepared by electrochemical deposition of PANI onto hydrous RuO 2 (PANI/RuO 2) and its supercapacitive properties are investigated using cyclic voltammetry. The specific capacitances of PANI/RuO 2 and hydrous RuO 2 electrodes are determined to be 708 and 517 F g −1 at 5 mV s −1, respectively. Simple electrodeposition of PANI on the hydrous RuO 2 can achieve comparatively greater capacitance values. 相似文献
6.
In this paper, Gd 3+ doped V 2O 5/Ti 3C 2T x MXene (GVO/MX) hierarchical architectures have been synthesized by wet chemical approach. As prepared GVO/MX composite, along undoped VO and unsupported GVO were well characterized by XRD, FESEM, EDX, FT-IR and BET techniques. Electrochemical performance of VO, GVO and GVO/MX was evaluated by CV, GCD and EIS measurements. Among the three electrodes, GVO/MX composite exhibited highest electrochemical activity with the optimum specific capacitance of 1024 Fg -1 at 10 mVs ?1. The specific capacitance of GVO/MX was ~1.7 and ~3 times higher than unsupported GVO (585 Fg -1) and VO (326 Fg -1), respectively. The cyclic life of GVO/MX with capacitance retention 96.12% was observed at 60 mVs ?1. EIS measurements showed reduction in electrochemical impedance for GVO/MX as compared to GVO and VO. The corresponding impedance values of Rct and Resr for GVO/MX were calculated as 18 Ω and 1.8 Ω, respectively. The superior capacitive ability of GVO/MX can be ascribed to its unique morphology, short diffusion path and high surface area of fabricated composite. Considering it, the present work provides a feasible strategy to fabricate highly effective electrode materials for next generation energy storage devices. 相似文献
7.
Iron disulfide (FeS 2) powders were successfully synthesized by hydrothermal method. Cetyltrimethylammonium bromide (CTAB) had a great influence
on the morphology, particle size, and electrochemical performance of the FeS 2 powders. The as-synthesized FeS 2 particles with CTAB had diameters of 2–4 μm and showed a sphere-like structure with sawtooth, while the counterpart prepared
without CTAB exhibited irregular morphology with diameters in the range of 0.1–0.4 μm. As anode materials for Li-ion batteries,
their electrochemical performances were investigated by galvanostatic charge–discharge test and electrochemical impedance
spectrum. The FeS 2 powder synthesized with CTAB can sustain 459 and 413 mAh g −1 at 89 and 445 mA g −1 after 35 cycles, respectively, much higher than those prepared without CTAB (411 and 316 mAh g −1). The enhanced rate capability and cycling stability were attributed to the less-hindered surface layer and better electrical
contact from the sawtooth-like surface and micro-sized sphere morphology, which led to enhanced process kinetics. 相似文献
8.
Three types of composite supercapacitor electrodes were prepared; electroactive polyaniline (PANI), PANI/multi-walled carbon
nanotube (CNT), and PANI/CNT/RuO 2. Specifically, the PANI and PANI/CNT were prepared by polymerization, and PANI/CNT/RuO 2 was prepared by electrochemical deposition of RuO 2 on the PANI/CNT matrix. Cyclic voltammetry between −0.2 and 0.8 V (vs. Ag/AgCl) at various scan rates was performed to investigate
the supercapacitive properties in an electrolyte solution of 1.0 M H 2SO 4. The PANI/CNT/RuO 2 electrode showed the highest specific capacitance at all scan rates (e.g., 441 and 392 F g −1 at 100 and 1,000 mV s −1, respectively). In contrast, the PANI/CNT electrode demonstrated the best capacitance retention (66%) after 10 4 cycles. Additional analysis including morphology and complex impedance spectroscopy suggested that with small loading of
RuO 2, an increase in capacitance was observed, but dissolution and/or detachment of RuO 2 species from the electrode might occur during cycling to reduce the cycle performance. 相似文献
9.
The dependence on morphology of the supercapacitive characteristics of manganese dioxide nanospheres (NSs) and nanorods (NRs)
was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and a series of electrochemical techniques.
Because the nanosized pores in MnO 2 NSs resulted in high surface area, MnO 2 electrodes made of NSs had higher specific capacitance (SC) than those made of NRs at current densities less than 2.0 A g −1. However, at current densities over 2.0 A g −1, the power density of MnO 2 electrodes composed of NRs was better than that of NSs. The high surface area and nanosized pores in MnO 2 NSs increase the number of redox active sites, which leads to high specific capacitance. On the other hand, the small pore
size in MnO 2 NSs restricts the rates of charge and discharge, thus limiting their power density. 相似文献
10.
A number of transition-metal borides were studied as anodic materials for neutral aqueous batteries. These borides are shown
to have considerably high electrochemical activities in neutral electrolytes. The discharge capacities for TiB 2 reach 1,350 mAh g −1 at a constant current density of 50 mA g −1, exceeding those for all the metal electrodes reported so far. Amorphous CoB x can deliver a discharge capacity of >650 mAh g −1, and even simply ball-milled FeB x can also give a discharge capacity of >200 mAh g −1. These results suggest the possible use of boride compounds as a large family of new anodic materials for constructing neutral
aqueous batteries with high electrochemical capacity and rate capability. 相似文献
11.
LiNi 0.8Co 0.2O 2 cathode powders for lithium-ion batteries were prepared by a modified sol–gel method with citric acid as chelating agent
and a small amount of hydroxypropyl cellulose as dispersant agent. The structure and morphology of LiNi 0.8Co 0.2O 2 powders calcined at various temperatures for 4 h in air were characterized by means of powder X-ray diffraction analyzer,
scanning electron microscope, thermogravimetric analyzer and differential thermal analyzer, and Brunauer–Emmett–Teller specific
surface area analyzer. The results show that LiNi 0.8Co 0.2O 2 powders calcined at 800 °C exhibit the best layered structure ordering and appear to have monodispersed particulates surface.
In addition, the electrochemical properties of LiNi 0.8Co 0.2O 2 powders as cathode material were investigated by the charge–discharge and cyclic voltammetry studies in a three-electrode
test cell. The initial charge–discharge studies indicate that LiNi 0.8Co 0.2O 2 cathode material obtained from the powders calcined at 800 °C shows the largest charge capacity of 231 mAh g −1 and the largest discharge capacity of 191 mAh g −1. And, the cyclic voltammetry studies indicate that Li + insertion and extraction in LiNi 0.8Co 0.2O 2 powders is reversible except for the first cycle. 相似文献
12.
Co 3O 4 nanorods have been successfully synthesized by thermal decomposition of the precursor prepared via a facile and efficient
microwave-assisted hydrothermal method, using cetyltrimethylammonium bromide (CTAB) with ordered chain structures as soft
template for the first time. The obtained Co 3O 4 was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM),
and electrochemical measurements. The results demonstrate that the as-synthesized nanorods are single crystalline with an
average diameter of about 20 to 50 nm and length up to several micrometers. Preliminary electrochemical studies, including
cyclic voltammetry (CV), galvanostatic charge–discharge, and electrochemical impedance spectroscopy (EIS) measurements, are
carried out in 6 M KOH electrolyte. Specific capacitance of 456 F g −1 for a single electrode could be achieved even after 500 cycles, suggesting its potential application in electrochemical capacitors.
This promising method could provide a universal green chemistry approach to synthesize other low-cost and environmentally
friendly transition metal hydroxide or oxide. 相似文献
13.
CoZn layered double hydroxide (LDH) or Co(OH)2 pseudocapacitive material has been prepared on the current collector of carbon fiber paper (CFP) using an eco-friendly one-step electrodeposition. Benefiting from its unique structural feature, the binder-free CoZn LDH/CFP electrode material realizes high specific capacitance of 1156 Fg?1 at a current density of 1 Ag?1 and excellent rate capability of 80% retention with 16 fold current density increment, which is much better than that of Co(OH)2 (617 Fg?1, 65%). Notably, the CoZn LDH/CFP can retain an outstanding electrochemical stability with a capacitance degradation of only 6% after 6000 charge–discharge cycles at 32 Ag?1. Moreover, an asymmetric supercapacitor (ASC) using CoZn LDH/CFP as a positive electrode and AC/CFP as a negative electrode has been assembled. The ASC exhibits a superior energy density of 30.0 Whkg?1 at a power density of 800 Wkg?1 with a specific capacitance up to 84.4 Fg?1 and a potential window wide to 1.6 V. These encouraging results indicate that CoZn LDH/CFP composite material has a great potential for next-generation energy conversion/storage devices. 相似文献
14.
This paper discusses the electrochemical behaviors of worm-like mesoporous carbon obtained in 1.0 mol L −1 LiClO 4/ethylene carbonate + dimethyl carbonate solution. The capacitance for nanoporous carbon system advances up to 147 F g −1 and a wide voltage window (2.5 V) for three electrode system was achieved. The specific energy and specific power reach as
high as 127.6 Wh kg −1 and 5.0 kW kg −1. These results show that worm-like mesoporous carbon can be used for high energy density and power density non-aqueous electrolyte
supercapacitors. 相似文献
15.
ZnO-based anodes are currently possessing drawbacks such as their low cyclic stability, high capacity fade, and relatively low electronic conductivity that prevent their widespread use in commercial batteries. A commercially available, patented MicNo morphology of ZnO is known to adopt the advantages of nanosize into bulk in the field of semiconductor and cosmetic technology. In this study, the electrochemical performance of ZnO having MicNo morphology and its potential use in Li-ion batteries were investigated. After 100 galvanostatic cycles at constant 100 mA/g current density, the retained capacity of MicNo is higher than nanosized ZnO-the starting powder for MicNo ZnO. On the contrary, at higher current densities of 500 or 1000 mA/g, the nano-ZnO showed better cyclability and lower capacity fade compared to MicNo ZnO. In cyclic voltammetry results, reduction in ZnO, LiZn, and Li 2Zn 3 formation was dominant during formation cycle of MicNo ZnO along with excellent reversibility. After lithiation, phase change from crystalline ZnO into metallic Zn and amorphous ZnO was observed from transmission electron microscopy analysis. Improved Li + diffusion in SEI and pore channels, better charge-transfer characteristics, poor electronic contact, and high EDL capacitance are other features of MicNo ZnO according to electrochemical impedance spectroscopy. 相似文献
16.
The electrochemical behavior of polycrystalline diamond films of different thickness (0.5–7 μm), grown by hot-filament CVD
method, was studied by electrochemical impedance spectroscopy and cyclic voltammetry. The differential capacitance, background
current, and potential window were measured in supporting electrolyte solution; the electrochemical kinetics, in [Fe(CN) 6] 3−/4− model redox system. With the increasing of the films thickness, the crystallite size increased; both the differential capacitance
and background current in the indifferent electrolyte, as well as the transfer coefficients in the redox system, decreased;
thus, the diamond electrode becomes as if less reversible. The effect of the films’ thickness is reduced to that of nondiamond
(amorphous) carbon contribution from intercrystalline boundaries on the electrochemical behavior of the polycrystalline diamond
electrodes. 相似文献
17.
With the use of lithium batteries increasing year by year, resulting in a large number of waste lithium-ion batteries generated, bringing pressure to the ecological system while also causing a waste of Co resources. Although Co-based catalysts are also of interest in the Li–CO 2 system, no research has been reported on the preparation of catalysts for value-added utilization of recovered Co. In this paper, Li–CO 2 batteries with Co 3O 4/CNT cathodes were prepared by environmentally friendly hydrothermal method employing cobalt oxalate recycled from waste lithium-ion batteries as a Co source in combination with commercial CNT. Unlike traditional noble metal and transition metal-based catalysts, which are expensive and complicated, this work can further reduce the cost of batteries by recycling valuable Co sources from waste lithium-ion batteries. As a result, the battery has the discharge capacity of 2728 mAh g ?1 at a current density of 100 mA g ?1. Not only that, but it can reach more than 85 cycles at a limited capacity of 400 mAh g ?1. 相似文献
18.
A mesoporous cobalt oxide (CoO) film has been successfully prepared by electrodeposition using surfactant Brij 56 as the structure-directing
agent. The scanning electron microscopy and transmission electron microscopy results indicate that the as-prepared CoO film
has a highly porous structure constructed by many interconnected nanoflakes with a thickness of about 20 nm. The CoO flakes
with continuous mesopores ranging from 5 to 10 nm arrange vertically to the substrate, forming a net-like structure and leaving
pores of 30–250 nm. As anodes for Li ion batteries, the porous CoO film exhibits higher coulombic efficiency, weaker polarization
and better cycling performance, compared to dense CoO film. The specific capacity after 50 cycles for the porous CoO film
electrode is 509 mAh g −1 at 1C rate, much higher than that of dense film (283 mAh g −1). The better electrochemical performances of the porous film are attributed to its highly porous morphology, which shortens
the Li ion diffusion paths within the bulk of CoO and relaxes the volume change caused by the reaction between CoO and Li
ion. 相似文献
19.
Transitional metal oxides are prevalent in the energy storage devices due to their remarkable electrochemical activity and charge storage capability. In this study, a spinel structured zinc cobaltite (ZnCo 2O 4) is doped with Ni and Cr to form a novel (Ni,Cr:ZnCo 2O 4) electrode material towards supercapacitor (SC) applications. Dopants served as a conductivity booster, particle size reducer and active sites provider benefitting the electrochemical activity. Comparatively, the doped sample delivered a higher capacitance value of 575 Fg -1 in the potential range of 0–0.6V with 1 M KOH solution as an electrolyte which is higher than that of the pristine material and better cyclic stability is improved from 82.2% to 90.24% for 2000 cycles. The specific capacitance value of 30 Fg -1 and 73 Fg -1 at 0.75 Ag -1 is achieved for the fabricated asymmetric supercapacitor device with Ni,Cr:ZnCo 2O 4 using Cu foil and Ni foam as current collector respectively. The device assembled with doped sample using Ni foam current collector has an energy density of 16.3 WhKg ?1 and a power density of 0.9 KWKg ?1 superseding the performance of the devices constructed with the pristine ZnCo 2O 4. The performance of Ni and Cr doped spinel structured zinc cobaltite device indicates a notable progress towards the direction of better performance supercapacitor applications. 相似文献
20.
Nanoplatelets of metal oxides with interesting porous structure were obtained by thermal treatment of Ni/Al hydrotalcite.
Structural and surface properties of the porous oxides were characterized by X-ray diffraction (XRD), transmission electron
microscopy (TEM and HRTEM), and N 2 adsorption–desorption. The electrochemical performance of the electrodes was investigated by cyclic voltammetry, electrochemical
impedance spectroscopy and constant current charge–discharge measurements. Ni/Al hydrotalcite calcined at 450 °C (NA-450)
displayed a maximum specific capacitance (419.0 F g −1) due to the porous structure with the highest specific surface area (142.3 m 2 g −1) and small pore size (4.4 nm). The present study shows the potential of NiO nanoplatelets composite material for electrochemical
pseudo-capacitors. 相似文献
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