Co-Effect of AlF3 and MgF2 Coating on the Electrochemical Performance of LiNi1/3Co1/3Mn1/3O2 Cathode Material under High Voltage

2015 ◽  
Vol 1088 ◽  
pp. 327-331
Author(s):  
Fei Fei Zhao ◽  
Dao Bin Mu ◽  
Xiong Xiong Hou ◽  
Lei Wang ◽  
Yong Huan Ren ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Cathode Material ◽  
Electrochemical Impedance ◽  
Impedance Spectra ◽  
X Ray Diffraction ◽  
Electrochemical Impedance Spectra ◽  
X Ray ◽  
Interface Charge ◽  
Interface Charge Transfer ◽  
Charge Discharge

AlF3 and MgF2 were applied to modify the surface of the LiNi1/3Co1/3Mn1/3O2 cathode material. The structural and electrochemical properties of the materials were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), charge–discharge tests and electrochemical impedance spectra (EIS). The results show that the 1 wt.% AlF3 and 1 wt.% MgF2 coated LiNi1/3Co1/3Mn1/3O2 (NCM333) cathode material exhibits an optimized electrochemical performance. It presents an initial capacity of 207.2mAh/g and 169.1mAh/g at 0.2C between 2.8V and 4.7V after charge-discharge 65 cycles. The rate performance is also enhanced because the coating decreases the interface charge transfer impedance.

Synthesis and Characterization of Li0.97K0.03FePO4/Graphene Composites by Carbonthermal Reduction Method

2014 ◽  
Vol 687-691 ◽  
pp. 4327-4330
Author(s):  
Yan Wang ◽  
Zhe Sheng Feng ◽  
Lu Lin Wang ◽  
Jin Ju Chen ◽  
Zhen Yu He
Keyword(s):  
Discharge Capacity ◽  
Photoelectron Spectroscopy ◽  
Reduction Method ◽  
Electrochemical Impedance ◽  
Impedance Spectra ◽  
X Ray Diffraction ◽  
Capacity Retention ◽  
Electrochemical Impedance Spectra ◽  
X Ray

Li0.97K0.03FePO4 and Li0.97K0.03FePO4/graphene composites were synthesized by carbothermal reduction method using acetylene black as carbon source. The structure and electrochemical properties of the prepared materials were investigated with X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, galvanostatic charge and discharge and electrochemical impedance spectra tests. The results indicated that K doping improves the cyclic stability of samples, the addition of small amounts of graphene results in better electronic properties on sample. Li0.97K0.03FePO4/graphene showed discharge capacity of 158.06 and 90.55 mAh g-1 at 0.1 C and 10 C, respectively. After the 50 cycle test at different rates, the reversible discharge capacity at 0.1 C was 158.58 mAh g-1, indicating the capacity retention ratio of 100.32%.

Electrochemical Performance of Mg-Doped Li2FeSiO4/C as Cathode Material for Lithium-Ion Batteries

2013 ◽  
Vol 310 ◽  
pp. 90-94 ◽  
Author(s):  
Xiao Bing Huang ◽  
Hong Hui Chen ◽  
Huang Rong Li ◽  
Qian Peng Yang ◽  
Shi Biao Zhou ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Rate Capability ◽  
Lithium Ion ◽  
Impedance Spectra ◽  
X Ray Diffraction ◽  
Electrochemical Impedance Spectra ◽  
Solid State Method ◽  
X Ray ◽  
Mg Doped ◽  
Discharge Test

Li2FeSiO4/C and Li1.97Mg0.03FeSiO4/C composites were successfully prepared by a solid-state method. Both samples were systematically investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), the charge-discharge test and electrochemical impedance spectra measurement, respectively. It was found that the Li1.97Mg0.03FeSiO4/C composite exhibited an excellent rate capability with a discharge capacity of 144mAh g-1 at 0.2C and 97mAh g-1 at 5C, and after 100 cycles at 1 C, 96% of its initial capacity was retained.

Few-Layered MoS2 Nanostructures for Highly Efficient Visible Light Photocatalysis

NANO ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. 1650114 ◽  
Author(s):  
Dan Li ◽  
Jianwei Li ◽  
Caiqin Han ◽  
Xinsheng Zhao ◽  
Haipeng Chu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Electrochemical Impedance ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
Electrochemical Impedance Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Hole Pair

Few-layered MoS2 nanostructures were successfully synthesized by a simple hydrothermal method without the addition of any catalysts or surfactants. Their morphology, structure and photocatalytic activity were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, electrochemical impedance spectra and UV-Vis absorption spectroscopy, respectively. These results show that the MoS2 nanostructures synthesized at 180[Formula: see text]C exhibit an optimal visible light photocatalytic activity (99%) in the degradation of Rhodamine B owing to the relatively easier adsorption of pollutants, higher visible light absorption and lower electron–hole pair recombination.

One-Pot Electrodeposition of NiS Nanoparticles as an Efficient Electrode for Nonenzymatic H2O2 and Glucose Sensors

NANO ◽  
2019 ◽  
Vol 14 (01) ◽  
pp. 1950010
Author(s):  
Zhiheng Huang ◽  
Chunchuan Gu ◽  
Jiajun Wen ◽  
Langlang Zhu ◽  
Mingzhen Zhang ◽  
...  
Keyword(s):  
Metal Ion ◽  
Electrochemical Impedance ◽  
Glucose Sensors ◽  
Cyclic Voltammograms ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra ◽  
One Pot ◽  
X Ray ◽  
First Time ◽  
Nis Nanoparticles

In this paper, a new and one-pot electrodeposition method was expanded for the preparation of NiS nanoparticles-based electrochemical biosensor using metal-ion complexes as a precursor. Thioacetamide was used to control the production rate of NiS nanoparticles for the first time. The proposed electrochemical sensor was characterized by energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscope (FESEM), cyclic voltammograms (CV), and electrochemical impedance spectra (EIS). Experiment parameters were optimized. Under the optimized condition, the prepared NiS-based biosensor exhibited excellent electrocatalytic oxidation of H2O2 and glucose due to their small size. It provided fast and sensitive strategy for detecting H2O2 and glucose in the range of 1–5000 and 1–1000[Formula: see text][Formula: see text]M. The detection limit of 0.257 and 0.3[Formula: see text][Formula: see text]M was obtained for H2O2 and glucose. The mechanisms were also analyzed. The proposed biosensor exhibited excellent anti-interference and repeatability. Furthermore, it was applied in the actual sample analysis, such as human blood serum.

Electrochemical Performance of Li4Ti5O12/TiO2/Li0.4TiO2/C Composite Prepared by the Electrospinning Method Using as Lithium Battery Anode Material

2016 ◽  
Vol 852 ◽  
pp. 959-962 ◽  
Author(s):  
Chun Hua Chen ◽  
Jia Jia Feng ◽  
Wei Quan Shao ◽  
Sha Ou Chen ◽  
Li Zhu He ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Raw Materials ◽  
Electronic Conductivity ◽  
Specific Capacity ◽  
Impedance Spectra ◽  
Fiber Structure ◽  
X Ray Diffraction ◽  
Electrochemical Impedance Spectra ◽  
Electrospinning Method ◽  
Better Than

Li4Ti5O12(LTO) and Li4Ti5O12/TiO2/Li0.4TiO2/C (LTO/C) composite were prepared by the electrospinning method using acetic acid, ethanol, butyl titanate, lithium acetate and PVP (K90) as the raw materials. The phase structure and the morphology were characterized by the X-ray diffraction (XRD) and the scanning electron microscopy (SEM), respectively. It was found that the specific capacity was 356mAh/g at 0.5C for the composite, which was higher than the theoretical specific capacity of the pure Li4Ti5O12 due to the inclusion of other phase. Moreover, the C-rate performance for the composite was also better than that of the pure Li4Ti5O12 resulting from the formation of carbon-based fiber structure. Electrochemical impedance spectra (EIS) revealed that the composite exhibited the improved electronic conductivity than that of Li4Ti5O12.

Electrochemical Performance Cr Doped Spinel LiMn2O4 Cathode for Lithium Ion Batteries

2014 ◽  
Vol 636 ◽  
pp. 49-53
Author(s):  
Si Qi Wen ◽  
Liang Chao Gao ◽  
Jia Li Wang ◽  
Lei Zhang ◽  
Zhi Cheng Yang ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Lithium Ion ◽  
Cycling Performance ◽  
Cycle Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Discharge Test

To improve the cycle performance of spinel LiMn2O4as the cathode of 4 V class lithium ion batteries, spinel were successfully prepared using the sol-gel method. The dependence of the physicochemical properties of the spinel LiCrxMn2-xO4(x=0,0.05,0.1,0.2,0.3,0.4) powders powder has been extensively investigated by using X-ray diffraction (XRD), scanning electron microscope (SEM), charge-discharge test and electrochemical impedance spectroscopy (EIS). The results show that as Mn is replaced by Cr, the initial capacity decreases, but the cycling performance improves due to stabilization of spinel structure. Of all, the LiCr0.2Mn1.8O4has best electrochemical performance, 107.6 mAhg-1discharge capacity, 96.1% of the retention after 50 cycles.

Influence of Nanosized α-Ni(OH)2 Addition on the Electrochemical Performance of β-Ni(OH)2 Electrode

2007 ◽  
Vol 121-123 ◽  
pp. 1265-1268 ◽  
Author(s):  
T.A. Han ◽  
J.P. Tu ◽  
Jian Bo Wu ◽  
Y.F. Yuan ◽  
Y. Li
Keyword(s):  
Electrochemical Performance ◽  
Active Material ◽  
Spherical Shape ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Galvanostatic Charge ◽  
X Ray ◽  
Co Precipitation ◽  
Charge Discharge ◽  
Scanning Electron

Al-substituted α-Ni(OH)2 was synthesized by a chemical co-precipitation. The as-prepared α-Ni(OH)2 particles were characterized by the means of X-ray diffraction (XRD) and scanning electron microscope (SEM). The obtained α-Ni(OH)2 particles were well crystallized, spherical shape with the particle sizes of 20-35 nm. The electrochemical performance of β-Ni(OH)2 electrode with addition of nanosized α-Ni(OH)2 was investigated by galvanostatic charge-discharge tests. The nanosized α-Ni(OH)2 as additive in the commercial microsized spherical β-Ni(OH)2 electrode improved the discharge capability. As compared to commercial β-Ni(OH)2 electrode, the electrode with nanosized α-Ni(OH)2 exhibited excellent better charge-discharge cycling stability. It may be a promising positive active material for alkaline secondary batteries.

Surface Modification of Spinel LiMn2O4 with Y2O3 for Lithium-Ion Battery

2011 ◽  
Vol 391-392 ◽  
pp. 1069-1074 ◽  
Author(s):  
Ying Bai ◽  
Feng Wu ◽  
Hua Tong Yang ◽  
Yu Zhong ◽  
Chuan Wu
Keyword(s):  
Surface Modification ◽  
Chemical Process ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Discharge Characteristics ◽  
X Ray ◽  
Passivating Films ◽  
Discharge Capacities ◽  
Charge Discharge

Spinel LiMn2O4was modified with Y2O3coating by a chemical process. The crystal structures of the as-prepared samples were investigated by X-ray diffraction (XRD). The charge/discharge characteristics of the modified samples were evaluated at different rates between 3.0 and 4.4V. The discharge capacities of 2.0 wt.% Y2O3-coated LiMn2O4are 116 mAh•g−1, 99.7mAh•g−1, 93.3mAh•g−1and 82.9mAh•g−1at 0.1C, 0.5C, 1C and 2C rates (at 20◦C). The cycle abilities improvement of the spinel LiMn2O4coated with Y2O3are demonstrated at elevated temperature (55◦C) and high rates (2C). From the analysis of electrochemical impedance spectroscopy (EIS), the improvement of cycle ability may be attributed to the suppression on the formation of the passivating films and the reduction of Mn dissolution, which result from the surface modification with Y2O3.

scholarly journals Facile Synthesis of Carbon Nanospheres with High Capability to Inhale Selenium Powder for Electrochemical Energy Storage

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6760
Author(s):  
Mustafa Khan ◽  
Xuli Ding ◽  
Hongda Zhao ◽  
Xinrong Ma ◽  
Yuxin Wang
Keyword(s):  
Electrochemical Performance ◽  
Current Density ◽  
Electrochemical Impedance ◽  
Discharge Rate ◽  
Specific Capacity ◽  
Rate Performance ◽  
X Ray Diffraction ◽  
Carbon Nanospheres ◽  
Surface Areas ◽  
Charge Discharge

Carbon–selenium composite positive electrode (CSs@Se) is engineered in this project using a melt diffusion approach with glucose as a precursor, and it demonstrates good electrochemical performance for lithium–selenium batteries. X-ray diffraction (XRD) and scanning electron microscopy (SEM) with EDS analysis are used to characterize the newly designed CSs@Se electrode. To complete the evaluation, electrochemical characterization such as charge–discharge (rate performance and cycle stability), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) tests are done. The findings show that selenium particles are distributed uniformly in mono-sized carbon spheres with enormous surface areas. Furthermore, the charge–discharge test demonstrates that the CSs@Se cathode has a rate performance of 104 mA h g−1 even at current density of 2500 mA g−1 and can sustain stable cycling for 70 cycles with a specific capacity of 270 mA h g−1 at current density of 25 mA g−1. The homogeneous diffusion of selenium particles in the produced spheres is credited with an improved electrochemical performance.

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