Reaction Mechanism of LiFePO4/C Cathode Materials Synthesized by Carbothermal Reduction Method

2010 ◽  
Vol 178 ◽  
pp. 248-253 ◽  
Author(s):  
Li Min Gao ◽  
Guang Chuan Liang ◽  
Li Wang ◽  
Xiao Ke Zhi ◽  
Xiao Fei Jie
Keyword(s):  
Carbothermal Reduction ◽  
Reduction Method ◽  
Intermediate Phase ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
X Ray ◽  
Reducing Atmosphere ◽  
Carbothermal Reduction Method ◽  
Lower Temperature

LiFePO4/C powders were synthesized by carbothermal reduction method using Li2CO3 (A.R), FePO4 (A.R) and glucose as raw materials. In this paper, the carbothermal reaction courses were characterized by Thermo-gravimetric (TG)/Differential Thermal Analysis (DTA), X-ray diffraction (XRD) and Fourier transform infrared (FTIR). It was found that the different synthesis temperatures and the different reducing atmosphere in systems could lead to different reactions, resulting in different final products and a direct impact on material performance. At around 350 °C LiFePO4 is directly formed without intermediate phase. In lower temperature of 400-500 °C, the sample included a certain amount of Li3PO4 and Fe2O3 impurity phases. When calcination temperature rose to 550 °C, the sample could be pure LiFePO4 phase.

Preparation of TiB2 Ultrafine Powders by Carbothermal Reduction

2016 ◽  
Vol 697 ◽  
pp. 58-61
Author(s):  
Jin Cheng Yu ◽  
Li Ma ◽  
Yu Jun Zhang ◽  
Hong Yu Gong ◽  
Li Wei Zhou
Keyword(s):  
Carbon Black ◽  
Carbothermal Reduction ◽  
Reduction Method ◽  
Raw Materials ◽  
Structural Evolution ◽  
Holding Time ◽  
X Ray Diffraction ◽  
X Ray ◽  
Boron Source ◽  
Different Content

TiO2, B2O3, H3BO3, B4C and carbon black were used as the raw materials to prepare TiB2 powders by carbothermal reduction method. The influence of different content of carbon black (13.6~14.8 wt%) on products was discussed. The effects of different boron sources and holding time (10~50 min) on the microstructure of TiB2 powders were also investigated. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to study the phase composition and structural evolution of the powder. The final results showed that hexagonal TiB2 crystal grain could be successfully synthesized without impurities when heated at 1700°C for 30 min in Ar atmosphere with the addition of 14.1 wt% carbon black. Submicrometric TiB2 powders range from 0.5 to 1.0 μm could be obtained when B4C was used as the boron source. The increase in holding time contributed to the grain growth and completion of chemical reactions, but could also result in oversintering.

EFFECTS OF DIFFERENT CARBON SOURCES ON PROPERTIES OF LiFePO4/C BY A CARBOTHERMAL REDUCTION METHOD

2010 ◽  
Vol 03 (03) ◽  
pp. 155-160 ◽  
Author(s):  
NING HUA ◽  
LIUMING SUO ◽  
CHENYUN WANG ◽  
YING HAN ◽  
XUEYA KANG
Keyword(s):  
Electron Microscopy ◽  
Carbothermal Reduction ◽  
Reduction Method ◽  
Carbon Sources ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbothermal Reduction Method ◽  
Excellent Electrochemical Performance ◽  
Rate Capacity ◽  
Mean Molecular Weight

The LiFePO 4/ C composite was prepared by carbothermal reduction method (CTR) with FePO 4 ⋅ 2 H 2 O , Li 2 CO 3 as starting materials, and acetylene black or polyethylene glycol (PEG; mean molecular weight of 10,000) as carbon sources. The structural and electrochemical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmittance electron microscopy (TEM), and charge–discharge tests. The results showed that LiFePO 4/ C is olivine-type phase, and the addition of carbon reduced the LiFePO 4 grain size with uniform distribution. The carbon is dispersed between the grains, forming a good electronic contact. The synthesized LiFePO 4 composites showed excellent electrochemical performance with initial discharge capacity of 161, 142 and 96 mAh ⋅ g-1 at 0.1 C, 1 C and 5 C, respectively and displays a robust rate capacity and stable cycling life.

Growth and Morphology of β-Si3N4 Nano-Belts by Carbothermal Reduction Nitridation of Used Silica Refractory Brick

2012 ◽  
Vol 624 ◽  
pp. 1-4 ◽  
Author(s):  
Wen Juan Li ◽  
Zi He Pan ◽  
Zhao Hui Huang ◽  
Yan Gai Liu ◽  
Ming Hao Fang
Keyword(s):  
Cross Section ◽  
Carbothermal Reduction ◽  
Raw Materials ◽  
Carbon Powder ◽  
X Ray Diffraction ◽  
Refractory Brick ◽  
X Ray ◽  
Vs Mechanism ◽  
Energy Disperse Spectrum ◽  
Silica Refractory

Silicon nitride (β-Si3N4) nano-belts had been synthesized by used silica bricks and carbon powder as raw materials through carbothermal reduction nitridation. The morphology and microstructure of β-Si3N4 nano-belts were characterized by scanning electron microscopy (SEM/HRSEM), energy disperse spectrum (EDS) and X-ray diffraction (XRD). Results showed that the well-crystallized β-Si3N4 nano-beltes were grown with thinness of 50-150nm and width of 3-5μm. The relatively purer β-Si3N4 were prone to be thin films with thinness of 150nm, while the as-grown SiCN (impurityβ-Si3N4with C elements) were presented as nanorods with cross section length of 150*150nm. Orientation growth mechanism by grain dislocation and vapor-solid (VS) mechanism were both involved in the growth of nanostructures of β-Si3N4 nano-beltes and SiCN nanorods.

Formation of TiC-Reinforced Iron Based Composite through Carbothermal Reduction of Hematite and Anatase

2010 ◽  
Vol 173 ◽  
pp. 116-121
Author(s):  
Mohd Salihin Hassin ◽  
Zuhailawati Hussain ◽  
Palaniandy Samayamutthirian
Keyword(s):  
Carbothermal Reduction ◽  
Milling Time ◽  
Constant Pressure ◽  
Raw Materials ◽  
Anatase Tio2 ◽  
Vacuum Furnace ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Hematite Fe2o3

In this research carbothermal reduction of mechanical activated hematite (Fe2O3), anatase (TiO2) and graphite (C) mixture was investigated. Mixture of raw materials with composition of Fe-20vol%TiC was mechanically activated in a planetary ball mill with different milling time (0h-60h) in argon atmosphere. X-ray diffraction (XRD) results showed the intensity of Fe2O3 reduced with milling time. The activated powders were pressed using cold pressing under a constant pressure (100MPa) and heat treated at 1100°C for sintering in a vacuum furnace. The increase in milling time resulted in the formation of iron (Fe) and titanium carbide (TiC) phase as confirmed by XRD result.

Synthesis of Aluminum Oxynitride Powder by Carbothermal Reduction Method

2010 ◽  
Vol 105-106 ◽  
pp. 791-793
Author(s):  
Ting Yan Tian ◽  
Hong Bing Du ◽  
Feng Sun ◽  
Hua Wei Jiang
Keyword(s):  
Activated Carbon ◽  
Carbothermal Reduction ◽  
Reduction Method ◽  
Raw Materials ◽  
Aluminum Oxynitride ◽  
Carbon Impurity ◽  
Sintering Additive ◽  
Carbothermal Reduction Method ◽  
Step Procedure ◽  
Hot Press Sintering

γ-aluminum oxynitride (γ-ALON) powder was prepared by carbothermal reduction method using γ-Al2O3 and activated carbon as raw materials. Effects of activated carbon content, synthesizing temperature, holding time and carbon impurity on ALON powder were studied. It was found a ‘two-step’ procedure, first sintering at about 1550°C-1650°C then at about 1750°C-1850°C, was effective to prepare high-purity ALON powder. The removal of carbon impurity was crucial for the preparation of ALON powder, which effectively improved the purity of ALON powder. The prepared powder was characterized by XRD and SEM, which indicated that pure ALON powder prepared by a ‘two-step’ procedure had well-developed crystalline and homogenous granularity. Transparent ALON ceramics were prepared by hot-press sintering at 1850~1900°C for up to 2~4h using ALON powder and some sintering additive, the transmission of sample with thickness of 1mm was 81% at infrared wave.

Synthesis of Al2OC Ceramic Powder by a Carbothermal Reduction Process

2014 ◽  
Vol 881-883 ◽  
pp. 1017-1020
Author(s):  
Shuang Shuang Ding ◽  
Peng Cui ◽  
Hong Xi Zhu ◽  
Cheng Ji Deng ◽  
Chao Yu
Keyword(s):  
Carbothermal Reduction ◽  
Raw Materials ◽  
Heating Temperature ◽  
Ceramic Powder ◽  
Reduction Process ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Argon Flow ◽  
Micro Morphology

A12OC ceramic powder was successfully synthesized via a carbothermal reduction method using Al2O3, B2O3 and activated carbon powders as raw materials. The effects of synthesis temperature on the phase transformation and micro-morphology of A12OC were investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that the content of A12OC in the products was increased with the increasing heating temperature. The optimized process for preparing A12OC was heating the mixtures at 1700 °C for 2 h in argon flow. A12OC particles synthesized at 1700 °C were hexagon plate-like with thickness of 5 μm and size of about 50 μm. Keywords: A12OC, synthesis, microstructure

Preparation of α-Al2O3 Powder by Microwave Pyrolysis

2014 ◽  
Vol 602-603 ◽  
pp. 88-92 ◽  
Author(s):  
Hao Chen ◽  
Bing Bing Fan ◽  
Xin Zhang ◽  
Xiao Xuan Pian ◽  
Rui Zhang
Keyword(s):  
Aluminum Hydroxide ◽  
High Purity ◽  
Raw Materials ◽  
Xrd Analysis ◽  
Fast Method ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
Microwave Pyrolysis ◽  
X Ray ◽  
Thermal Analyzer

A fast method of microwave pyrolysis was provided to prepare α-Al2O3 powders. Aluminum hydroxide and Aluminum ammonium sulfate doclecahydrate were used as raw materials to obtain α-aluminum oxide powder by microwave pyrolysis, respectively. Thermo-Gravimetric/Differential Thermal Analyzer (TG/DTA) and X-ray Diffraction (XRD) analysis were employed to investigate pyrolysis process and the transformation of metastables Al2O3 in the process of heating different precursors. Meanwhile, Flied Emission Scanning Electron Microscopy (FESEM) was applied to observe microstructure and grain growth, and the phase composition was characterized by XRD. The results indicated that the high purity α-Al2O3 was obtained which met the demands of market, and the sample obtained from aluminum hydroxide performed high purity, small particle size and, while the sample from ammonium aluminum sulfate showed lower purity and larger grain size.

Development of Decorative Ceramic Glaze from Palm Fiber Ash

2016 ◽  
Vol 690 ◽  
pp. 259-263
Author(s):  
Mohd Al Amin bin Muhamad Nor ◽  
Nur Hawa Hazwani Ya’acob
Keyword(s):  
Calcium Carbonate ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
Yellow Colour ◽  
Palm Fiber ◽  
X Ray ◽  
Ceramic Glaze ◽  
Ball Clay ◽  
Lower Temperature ◽  
Decorative Ceramic

Palm fiber ashes are the industrial waste which is abundantly available in Malaysia. In this study, palm fiber ash were used to produce decorative ceramic glaze. The content of minerals in the palm fiber ash were analyzed by using X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF), respectively. The formulations of glaze with different composition of raw materials were studied by adding different amount of calcium carbonate and feldspar. The glaze slurries then coated on ball clay body bisque which was obtained from Kg. Dengir and sintered at 1200 ° C for two hours.The glaze was characterized in term of its physical appearance such as type of glaze and colour. Both glossy and matte glaze produced by using different composition of glaze formulation. The presence of silica minerals (79 %) contributed to glossy surface to the glaze. It is clearly seen that the glossiness of glaze improved by increasing amount of feldspar. Feldspar acts as fluxing agent which form a glassy phase at lower temperature. In addition, the presence of small amount of iron oxide (2.2 wt.%) contributed to brown colour of glaze. An addition of calcium carbonate give effect to the colour of glaze, which change from brown to yellow colour as amount of CaCO3 increased. As a conclusion, the palm fibre ashes were highly suitable to supply abundant and cheap raw materials to produce decorative ceramic glaze.

The Synthesis of TiC Powders by Carbothermal Reduction Method in Vacuum

2014 ◽  
Vol 1064 ◽  
pp. 62-65
Author(s):  
Xue Tan Ren ◽  
Yan Chun Liu ◽  
Shui Hui Chen ◽  
Lai Guang Hou ◽  
Guo Long Wang ◽  
...  
Keyword(s):  
Carbon Black ◽  
Crystalline Phase ◽  
Carbothermal Reduction ◽  
Single Phase ◽  
Reduction Method ◽  
Raw Materials ◽  
Molar Ratio ◽  
Carbothermal Reduction Method ◽  
System Pressure

The TiC powders were synthesized by carbothermal reduction of TiO2in vacuum using the titania and carbon black as raw materials. The molar ratio of C to TiO2was 3:1. The crystalline phase, microstructure and morphology of the obtained samples were investigated by XRD and SEM. The results show that single-phase and well-crystallized TiC powders were obtained at 1300°C for 1h when the system pressure was 20 Pa. The particle morphologies are composed of fine grains about 200 nm.

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