Electrochemical Properties of LiFePO4/C Composite by Spray-Drying Method

2013 ◽  
Vol 643 ◽  
pp. 96-99 ◽  
Author(s):  
Yi Jie Gu ◽  
Fei Xiang Hao ◽  
Yun Bo Chen ◽  
Hong Quan Liu ◽  
Yan Min Wang ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Spray Drying ◽  
Discharge Capacity ◽  
Electrochemical Impedance ◽  
Drying Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Discharge Capacity ◽  
Conductive Additive ◽  
Charge Discharge

LiFePO4/C composite cathode materials were synthesized by spray-drying method using LiH2PO4 and Fe2O3 as raw materials and amylum as conductive additive and reducing agent. The microstructure of the samples was characterized by X-ray diffraction; charge/discharge cycling performance and electrochemical impedance spectroscopy (EIS) were used to characterize their electrochemical properties. X-ray diffraction result showed that LiFePO4/C composite has an order olivine structure with space group of Pnma. The charge/discharge tests showed that the cathode material has a high discharge capacity of 140.8mAh/g after 5 cycles at 0.1C rate. And after 100 cycles at 1C rate, the discharge capacity is 108.4mAh/g.

scholarly journals Structural and Electrochemical Properties of Lithium Nickel Oxide Thin Films

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Gyu-bong Cho ◽  
Tae-hoon Kwon ◽  
Tae-hyun Nam ◽  
Sun-chul Huh ◽  
Byeong-keun Choi ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrochemical Properties ◽  
Discharge Capacity ◽  
Oxygen Deficiency ◽  
Oxide Phase ◽  
Rf Magnetron Sputtering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lithium Nickel Oxide

LiNiO2thin films were fabricated by RF magnetron sputtering. The microstructure of the films was determined by X-ray diffraction and field-emission scanning electron microscopy. The electrochemical properties were investigated with a battery cycler using coin-type half-cells. The LiNiO2thin films annealed below 500°C had the surface carbonate. The results suggest that surface carbonate interrupted the Li intercalation and deintercalation during charge/discharge. Although the annealing process enhanced the crystallization of LiNiO2, the capacity did not increase. When the annealing temperature was increased to 600°C, the FeCrNiO4oxide phase was generated and the discharge capacity decreased due to an oxygen deficiency in the LiNiO2thin film. The ZrO2-coated LiNiO2thin film provided an improved discharge capacity compared to bare LiNiO2thin film suggesting that the improved electrochemical characteristic may be attributed to the inhibition of surface carbonate by ZrO2coating layer.

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%.

Microstructures and Electrochemical Properties of La0.7Ce0.3Ni3.7Co0.7-xAl0.2Mn0.4(Fe0.43B0.57)x (x = 0-0.4) Hydrogen Storage Alloys

2012 ◽  
Vol 608-609 ◽  
pp. 917-920
Author(s):  
Yu Zhou ◽  
Yan Ping Fan ◽  
Xian Yun Peng ◽  
Bao Zhong Liu
Keyword(s):  
Hydrogen Storage ◽  
Electrochemical Properties ◽  
Discharge Capacity ◽  
Secondary Phase ◽  
Cycling Stability ◽  
High Rate ◽  
X Ray Diffraction ◽  
Hydrogen Storage Alloys ◽  
X Ray ◽  
The Matrix

X-ray diffraction results indicate that pristine alloy has a single LaNi5 phase and the alloys containing Fe0.43B0.57 consist of the matrix LaNi5 phase and the La3Ni13B2 secondary phase. The abundance of La3Ni13B2 phase increases with increasing x value. Maximum discharge capacity of the alloy electrodes monotonically decreases from 336.1 mAh/g (x = 0) to 281.2 mAh/g (x = 0.4). High-rate dischargeability of the alloy electrodes first increases with increasing x from 0 to 0.20, and then decreases when x increases to 0.4. Cycling stability decreases with increasing x from 0 to 0.4.

The Morphology of Si-K-HAs Composite Prepared by Spray Drying

2019 ◽  
Vol 966 ◽  
pp. 19-24
Author(s):  
Srie Muljani ◽  
Heru Setyawan ◽  
Ketut Sumada
Keyword(s):  
Surface Area ◽  
Spray Drying ◽  
Humic Substance ◽  
Spherical Particles ◽  
Precipitation Method ◽  
Infrared Spectrometry ◽  
Drying Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spray Dried

The silica potassium humic substance (Si-K-HAs) composite have been produce by spray drying successfully. In the previous study the preparation of Si-K-HAs gel by precipitation method required the addition of acid so that Si-K-HAs gel product contains acid salts. This study was develope spray drying method in order to eliminate the use of acid. The mixture of potassium silicate, cellulose and humic potassium solution was mixed with varying volume ratios and flowed into a spray dryer to produce Si-K-HAs powder. The used of cellulose (CMC) in this study acts as a homogeneous agent so that silica and humic substance can be completely mixed at controlled viscosity. Si-K-HAs products were characterized by Scanning electron microscopy (SEM), X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), and Surface area analytical (SAA). The result showed that the Si-K-HAs composite prepared by spray dryers have spherical particles, SiO2 in the range of 48-50%, K2O in the range of 49-50%. The present of cellulose caused the increasing of Si-K-HAs particle size e.g 17.30 μm prepared without CMC to 41.11 μm prepared with addition of 100g of CMC. The presence of cellulose can also increase the surface area of the spray-dried Si-K-HAs particles from 111.92 m2g-1; 163.241 m2g-1.

Preparation of Co-B Alloy with the Assistance of the Sonication and its Electrochemical Properties

2017 ◽  
Vol 727 ◽  
pp. 751-755 ◽  
Author(s):  
Wei Zhao ◽  
Yi Lin Liao ◽  
Jian Ling Huang ◽  
Hai Liang Chu ◽  
Shu Jun Qiu ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Discharge Capacity ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Chemical Reduction ◽  
Negative Electrode ◽  
Rechargeable Batteries ◽  
X Ray Diffraction ◽  
Discharge Current Density ◽  
Negative Electrode Materials

In order to enhance the electrochemical properties of Co-B alloys used as negative electrode materials of alkaline rechargeable batteries, Co-B alloy was successfully prepared by a chemical reduction method with the assistance of the sonication. The phase structure and the surface morphology of the as-prepared Co-B alloys were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen physisorption. Moreover, the electrochemical performance was characterized by galvonostatic charge-discharge tests, electrochemical impedance spectroscopy (EIS) and anodic polarization (AP). Co-B alloy prepared with the assistance of the sonication consists of small particles with a uniform distribution. The electrochemical measurements showed that at a discharge current density of 100 mA/g, the initial discharge capacity was 858.1 mAh/g and the discharge capacity was 322.6 mA/g even at the 100th cycle with the capacity retention of 37.6%.

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 Nano-CL-20/HMX Cocrystal Explosive for Significantly Reduced Mechanical Sensitivity

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Chongwei An ◽  
Hequn Li ◽  
Baoyun Ye ◽  
Jingyu Wang
Keyword(s):  
Spray Drying ◽  
Raw Materials ◽  
Drop Height ◽  
Drying Method ◽  
X Ray Diffraction ◽  
Mechanical Sensitivity ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Friction Sensitivity ◽  
Scanning Electron

Spray drying method was used to prepare cocrystals of hexanitrohexaazaisowurtzitane (CL-20) and cyclotetramethylene tetranitramine (HMX). Raw materials and cocrystals were characterized using scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, Raman spectroscopy, and Fourier transform infrared spectroscopy. Impact and friction sensitivity of cocrystals were tested and analyzed. Results show that, after preparation by spray drying method, microparticles were spherical in shape and 0.5–5 µm in size. Particles formed aggregates of numerous tiny plate-like cocrystals, whereas CL-20/HMX cocrystals had thicknesses of below 100 nm. Cocrystals were formed by C–H⋯O bonding between –NO2 (CL-20) and –CH2– (HMX). Nanococrystal explosives exhibited drop height of 47.3 cm, and friction demonstrated explosion probability of 64%. Compared with raw HMX, cocrystals displayed significantly reduced mechanical sensitivity.

Surface modification and electrochemical properties of activated carbons for supercapacitor electrodes

2015 ◽  
Vol 29 (Supplement 1) ◽  
pp. 1550254 ◽  
Author(s):  
Dan Yang ◽  
Wenmei Qiu ◽  
Jingcai Xu ◽  
Yanbing Han ◽  
Hongxiao Jin ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Specific Capacitance ◽  
Activated Carbons ◽  
Chemical Properties ◽  
Bet Surface Area ◽  
Surface Chemical ◽  
X Ray Diffraction ◽  
Galvanostatic Charge ◽  
X Ray ◽  
Charge Discharge

Modifications with different acids (HNO3, H2SO4, HCl and HF, respectively) were introduced to treat the activated carbons (ACs) surface. The microstructures and surface chemical properties were discussed by X-ray diffraction (XRD), thermogravimetric analysis (TGA), ASAP, Raman spectra and Fourier transform infrared (FTIR) spectra. The ACs electrode-based supercapacitors were assembled with 6 mol ⋅ L[Formula: see text] KOH electrolyte. The electrochemical properties were studied by galvanostatic charge–discharge and cyclic voltammetry. The results indicated that although the BET surface area of modified ACs decreased, the functional groups were introduced and the ash contents were reduced on the surface of ACs, receiving larger specific capacitance to initial AC. The specific capacitance of ACs modified with HCl, H2SO4, HF and HNO3 increased by 31.4%, 23%, 21% and 11.6%, respectively.

Effect of Annealing Treatment on Structure and Electrochemical Properties of LaNi4.5Co0.25Al0.25 Alloy with Low Co Content

2013 ◽  
Vol 788 ◽  
pp. 141-146
Author(s):  
Feng Wang ◽  
Huai Ying Zhou ◽  
Jiang Wang ◽  
Zhong Min Wang ◽  
Huai Gang Zhang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electrochemical Properties ◽  
Discharge Capacity ◽  
Annealing Treatment ◽  
Electrochemical Measurement ◽  
X Ray Diffraction ◽  
Capacity Retention ◽  
X Ray ◽  
The Matrix ◽  
Suitable Treatment

The effect of annealing treatment on the structure and electrochemical properties of LaNi4.5Co0.25Al0.25 alloy was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurement. XRD results show that the matrix phases are still LaNi5 (hexagonal CaCu5 type structure) but the intensity peaks become sharper after heat treatment. Electrochemical experiments at 301 K indicate that annealing treatment can significantly improve the discharge capacity and cyclic stability of LaNi4.5Co0.25Al0.25 alloy at suitable treatment condition. The alloy has the best discharge capacity (324.4 mAg-1) due to its composition homogenization after heat treatment at 1373 K/8 h, while the best capacity retention is about 80.12 % because of lower expansion rate and better anti-pulverization ability after heat treatment at 1273 K/8 h.

Ag Doped Co3O4 Nanowire Arrays as an Electrode Material for Electrochemical Capacitors

2012 ◽  
Vol 268-270 ◽  
pp. 157-163 ◽  
Author(s):  
Yang Xu ◽  
Ji Chun Huang ◽  
Lin Cheng ◽  
Dian Xue Cao ◽  
Gui Ling Wang
Keyword(s):  
Electrochemical Impedance ◽  
Nickel Foam ◽  
Nanowire Arrays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Growth Method ◽  
Template Free ◽  
A Current ◽  
Charge Discharge ◽  
Discharge Test

Co3O4 nanowire arrays freely standing on nickel foam are prepared via a template-free growth method，and it is doped by Ag via electrodeposition method (denoted as NWA-Ag/Co3O4，NWA represents Nanowire Arrays). The morphology of NWA-Ag/Co3O4 is examined by scanning electron microscopy. The phase structure of the NWA-Ag/Co3O4 electrode is characterized by X-ray diffraction spectroscopy. The supercapacitance behavior of the NWA-Ag/Co3O4 electrodes is investigated by cyclic voltammetry, galvanostatic charge/discharge test and electrochemical impedance spectroscopy. The results show that the nanowire arrays densely cover the nickel foam substrate and have diameters around 250 nm. The NWA-Ag/Co3O4 electrodes exhibit a specific capacitance of 1009 F g−1 at a current density of 5 mA cm-2 in 6.0 mol dm-3 KOH electrolyte. The capacitance loss is less than 6.5% after 500 charge/discharge cycles at 10 mA cm-2 and with columbic efficiency higher than 97.5%.

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