Preparing composites of Ni–Al layered double hydroxide/graphene electrode for supercapacitors and their electrochemical properties

2020 ◽  
Vol 10 (8) ◽  
pp. 1364-1368 ◽  
Author(s):  
Yunlong Zhou ◽  
Dan Yu ◽  
Junwen Peng ◽  
Xiaofang Chen ◽  
Zhibiao Hu

The composites of Ni–Al layered double hydroxide (Ni–Al LDH)/graphene (GR) had been synthesized through the hydrothermal route in this work. The mechanism of the composites depended on XRD. Meanwhile, SEM was used to record the morphological structure of the composites. The electrochemical properties were analyzed through the charge-discharge of constant current, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The composites of Ni–Al LDH/GR possessed a layered structure and the structure was uniformly dispersed on the graphene. The given discharge capacity of the composites of Ni–Al LDH/GR was higher than the value of bare Ni–Al LDH, which was approximately 400 F · g–1 in the speed of 1 A g–1; Meanwhile, the capacitance retention was still more than 1 time higher compared with the value of Ni–Al LDH for 500 cycles at 1 A g–1.

2010 ◽  
Vol 03 (03) ◽  
pp. 161-164 ◽  
Author(s):  
XI LONG ◽  
CHUNXIA ZHAO ◽  
WEN CHEN

The present paper studies a kind of mesoporous carbon (MC) with high electrochemical performance, which was prepared by vapor infiltration method. The microstructure and electrochemical properties of the mesoporous carbon were investigated by transmission electron microscopy (TEM), nitrogen adsorption–desorption isotherms, cyclic voltammetry (CV), constant current charge–discharge cycling (CD), and the long-term stability test. The results indicated that the mesoporous carbon has an ordered mesoporous structure, with pore size of about 3.87 nm and surface areas of 1087 m2 ⋅ g-1. The cyclic voltammetry curve reveals typical electrical double-layer capacitor property. After 200 cycles, the CV curves can almost be overlapped, which indicates excellent cycling stability. From the charge/discharge cycling, the specific capacitance of MC is 117 F ⋅ cm-1 in 1.0 M KNO3 electrolyte media at a scan rate of 1.0 mV ⋅ s-1, which decays with increasing current density. The charge–discharge efficiency also decays with it.


2011 ◽  
Vol 236-238 ◽  
pp. 694-697 ◽  
Author(s):  
Ling Zhi Zhu ◽  
En Shan Han ◽  
Ji Lin Cao

NiS was synthesized were prepared by hydrothermal and mechanical alloying routes, respectively, and their microstructures as well as physical and electrochemical properties have been characterized and compared. Based on XRD and SEM analyses, the NiS crystallites with nanoplate structure formed directly during a hydrothermal process. Compared with the mechanical alloying route, the hydrothermal route led to better dispersed nanoparticles with a narrower size distribution. And the electrochemical properties of the materials were characterized by charge-discharge testing and Cyclic-voltammetry. NiS were prepared by hydrothermal show proper cycling properties, its first discharge specific capacity was 584.6mAh/g.


2017 ◽  
Vol 727 ◽  
pp. 698-704 ◽  
Author(s):  
Xian Wei Wang ◽  
Xiao Er Wang ◽  
Hui Chao Zhang ◽  
Qian Qian Zhu ◽  
Dong Li Zheng ◽  
...  

The structural and electrochemical properties of lanthanum manganate (LaMnO3) powder prepared by the sol-gel method are researched in this article. The powder calcined at 600 °C showed amorphous, and the powder calcined at 700-800 °C showed the pure phase of the LaMnO3. The grains with the size of about 80-120 nm were agglomerating together. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical properties in alkaline environment. The electrochemical properties calcined at 700 °C showed a specific capacitance of 73 F/g at the current density of 0.5 A/g. The raw materials for preparing the LaMnO3 powder are cheap, and the operation method is simple.


2015 ◽  
Vol 1120-1121 ◽  
pp. 554-558 ◽  
Author(s):  
Juan Mei Wang ◽  
Bing Ren ◽  
Ying Lin Yan ◽  
Qing Zhang ◽  
Yan Wang

In this work, spherical LiFePO4/C composite had been synthesized by co-precipitation and spray drying method. The structure, morphology and electrochemical properties of the samples were characterized by X-ray diffraction (XRD), scanning electron micrograph (SEM), transmission electron microscope (TEM), constant current charge-discharge tests and electrochemical impedance spectroscopy (EIS) tests. The spherical LiFePO4/C particles consisted of a number of smaller grains. The results showed that the morphology of LiFePO4/C particles seriously affected the Li-ion diffusion coefficient and electrochemical properties of lithium ion batteries. Electrochemical tests revealed the spherical LiFePO4/C composite had excellent Li-ion diffusion coefficient which was calculated to be 1.065×10-11 cm2/s and discharge capacity of 149 (0.1 C), 139 (0.2 C), 133 (0.5 C), 129 (1 C) and 124 mAhg-1(2 C). After 50 cycles, the capacity retention rate was still 93.5%.


Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3487
Author(s):  
Ashraf Abdel-Ghany ◽  
Ahmed M. Hashem ◽  
Alain Mauger ◽  
Christian M. Julien

Lithium-rich layered oxides are recognized as promising materials for Li-ion batteries, owing to higher capacity than the currently available commercialized cathode, for their lower cost. However, their voltage decay and cycling instability during the charge/discharge process are problems that need to be solved before their practical application can be envisioned. These problems are mainly associated with a phase transition of the surface layer from the layered structure to the spinel structure. In this paper, we report the AlF3-coating of the Li-rich Co-free layered Li1.2Ni0.2Mn0.6O2 (LLNMO) oxide as an effective strategy to solve these problems. The samples were synthesized via the hydrothermal route that insures a very good crystallization in the layered structure, probed by XRD, energy-dispersive X-ray (EDX) spectroscopy, and Raman spectroscopy. The hydrothermally synthesized samples before and after AlF3 coating are well crystallized in the layered structure with particle sizes of about 180 nm (crystallites of ~65 nm), with high porosity (pore size 5 nm) determined by Brunauer–Emmett–Teller (BET) specific surface area method. Subsequent improvements in discharge capacity are obtained with a ~5-nm thick coating layer. AlF3-coated Li1.2Ni0.2Mn0.6O2 delivers a capacity of 248 mAh g−1 stable over the 100 cycles, and it exhibits a voltage fading rate of 1.40 mV per cycle. According to the analysis from galvanostatic charge-discharge and electrochemical impedance spectroscopy, the electrochemical performance enhancement is discussed and compared with literature data. Post-mortem analysis confirms that the AlF3 coating is a very efficient surface modification to improve the stability of the layered phase of the Li-rich material, at the origin of the significant improvement of the electrochemical properties.


2014 ◽  
Vol 936 ◽  
pp. 496-502
Author(s):  
Xue Bu Hu ◽  
Zi Ji Lin ◽  
Yong Long Zhang

A hybrid battery-supercapacitor (LiFePO4+AC)/Li4Ti5O12 using a Li4Ti5O12 anode and a LiFePO4/activated carbon (AC) composite cathode was built. The electrochemical performances of the hybrid battery-supercapacitor (LiFePO4+AC)/Li4Ti5O12 were characterized by constant current charge-discharge, rate charge-discharge, electrochemical impedance spectra, internal resistance, leakage current, self-discharge and cycle performance testing. The results show that (LiFePO4+AC)/Li4Ti5O12 hybrid battery-supercapacitors have rapid charge-discharge performance, high energy density, long cycle life, low resistance, low leakage current and self-discharge rate, which meet the requirements of practical power supply and can be applied in auxiliary power supplies for hybrid electric vehicles. At 4C rate, the capacity loss of (LiFePO4+AC)/Li4Ti5O12 hybrid battery-supercapacitors in constant current mode is no more than 7.71% after 2000 cycles, and the capacity loss in constant current-constant voltage mode is no more than 4.51% after 1500 cycles.


Author(s):  
Aqib Muzaffar ◽  
Keerthana Muthusamy ◽  
M. Basheer Ahamed

Ferrous nitrate/nickel oxide {Fe(NO3)2–NiO} nanocomposite was synthesized via two-step facile hydrothermal route. The nanocomposite exhibits crystalline structure as unveiled by X-ray diffraction (XRD) pattern, while as the scanning electron microscope (SEM) images divulge spherical morphologies for both Fe(NO3)2 as well as NiO nanoparticles differentiating from each other in size. Cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques were used to investigate supercapacitive behavior of the symmetrically fabricated nanocomposite electrode configuration using aqueous KOH as the electrolyte. The CV analyses demonstrate dominant electrical double layer capacitance (EDLC) behavior in the potential range of 0–1 V. From charge–discharge curves, the maximum specific capacitance calculated was 460 F g−1 corresponding to the energy density of 16 W h kg−1 at a high power density of 250 W kg−1. EIS data affiliate well with the CV and GCD results justifying the maximum contribution of specific capacitance due to double layer capacitance. The nanocomposite retained 84% of its original capacitance after 1000 cycles and yielded maximum efficiency of 78%.


2018 ◽  
Vol 165 (2) ◽  
pp. A407-A415 ◽  
Author(s):  
Hui Li ◽  
F. Musharavati ◽  
Jingtao Sun ◽  
Fadi Jaber ◽  
Erfan Zalnezhad ◽  
...  

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