Characteristics of Mesophase Pitch-Based Carbon Fibers as Anode Materials for Lithium Secondary Cells

1995 ◽  
Vol 393 ◽  
Author(s):  
Toshio Tamaki
Keyword(s):  
Carbon Fiber ◽  
Electrochemical Properties ◽  
Carbon Fibers ◽  
Discharge Capacity ◽  
Anode Materials ◽  
Mesophase Pitch ◽  
Good Efficiency ◽  
Heat Treated ◽  
Initial Charge ◽  
Discharge Efficiency

ABSTRACTMesophase pitch-based Carbon Fibers(MPCF) have been investigated as anode materials for lithium secondary cells by examining their physical and electrochemical properties. Discharge capacity and initial charge-discharge efficiency of the materials were studied in relation to the heat treatment temperatures of MPCF. Carbon fiber which was heat treated at about 3,000’C gave the highest discharge capacity(over 300mAh/g), good efficiency (92%) and superior current capability (600mA/g). Carbon fiber heat treated at less than 1,000·C, also has superior discharge capacity(over 500mAh/g) at the first cycle, however efficiency was relatively low. Some of the relationships between structure of MPCF and electrochemical properties are discussed below.

Characteristics of Boron Doped Mesophase Pitch-Based Carbon Fibers as Anode Materials for Lithium Secondary Cells

1997 ◽  
Vol 496 ◽  
Author(s):  
Toshio Tamaki ◽  
Toshifumi Kawamura ◽  
Yoshinori Yamazaki
Keyword(s):  
Carbon Fibers ◽  
Discharge Capacity ◽  
Anode Materials ◽  
Mesophase Pitch ◽  
Good Efficiency ◽  
High Discharge Capacity ◽  
Boron Doped ◽  
Heat Treated ◽  
Battery Capacity ◽  
Initial Charge

AbstractMesophase pitch-based Carbon Fibers(MCF) have been investigated as anode materials for lithium secondary cells by examining their physical and electrochemical properties. Discharge capacity and initial charge-discharge efficiency of the materials were studied in relation to the heat treatment temperatures of MCF. MCF heat treated at about 3,000° C gave high discharge capacity over 310mAh/g, good efficiency (93 %) and superior current capability of 600mA/g (6mA/cm2). On the other hand, to improve the battery capacity, Boron was doped to the fiber about several % by adding B4C to the pre-carbonized milled fibers and then heat-treated up to 3000°C in Ar. Then heat treated at 2,500°C under vacuum condition to remove remained B 4 C. The structure of Boron-doped fibers was characterized and compared with that of non-doped standard fibers, and also Li ion battery performances are evaluated. The Boron-doped MCF indicated improvement in graphitization and increased discharge capacity as high as 360mAh/g. The voltammograms of both fibers are different from each other. The cell mechanism is discussed based on the unique structure of Boron-doping to the MCF is very effective for the battery performance.

Structure and electrochemical properties of Sm-doped Li4Ti5O12 as anode material for lithium-ion batteries

RSC Advances ◽  
2016 ◽  
Vol 6 (19) ◽  
pp. 15492-15500 ◽  
Author(s):  
Zhanyu Li ◽  
Jianling Li ◽  
Yuguang Zhao ◽  
Kai Yang ◽  
Fei Gao ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Lithium Ion Batteries ◽  
Anode Material ◽  
Discharge Capacity ◽  
Anode Materials ◽  
Rate Capability ◽  
Lithium Ion ◽  
Cycling Performance

Sm doping has a great impact on discharge capacity, rate capability and cycling performance of LTO anode materials for lithium-ion batteries.

Structures and physical properties of carbon fibers from coal tar mesophase pitch

1987 ◽  
Vol 2 (6) ◽  
pp. 850-857 ◽  
Author(s):  
T. Hamada ◽  
T. Nishida ◽  
Y. Sajiki ◽  
M. Matsumoto ◽  
M. Endo
Keyword(s):  
Heat Treatment ◽  
Carbon Fibers ◽  
Coal Tar ◽  
Transverse Cross Section ◽  
Mesophase Pitch ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transverse Magnetoresistance ◽  
Heat Treated ◽  
Degree Of Graphitization

Carbon fibers having various types of structures were prepared by spinning coal tar mesophase pitch, followed by thermosetting and heat treatment at high temperature. Two kinds of spinning—spinning with stirring the pitch above a capillary and without stirring—have been tried to form pitch fibers from coal tar mesophase pitch. Carbon fibers obtained from mesophase pitch and spun without stirring have a radial transverse structure where the graphite layers are arranged radially in the transverse cross section of the fibers. Carbon fibers made with a stirring system can have random, onion, and a novel “quasionion structure” by changing the spinning conditions. Carbon fibers spun with stirring are less graphitizable than those spun without stirring. No separation of the ten diffraction bands into 100 and 101 peaks and no appearance of a 112 peak were observed by x-ray diffraction when the fibers were heat treated at 2700°C, whereas carbon fibers spun without stirring show clear evidence of graphitization by heat treatment at 2700°C. Transverse magnetoresistance effects at 77 K, (Δρ/ρ)t have been measured to characterize the structure of the carbon fibers. The carbon fibers spun with stirring and heat treated at 2500°C generally exhibit a negative transverse magnetoresistance effect, whereas the carbon fibers spun without stirring exhibit a positive magnetoresistance. Good correlations are found among d002, Lc (002), transverse magnetoresistance, and resistivity at room temperature of carbon fibers spun under various conditions and heat treated at 2500°C. The tensile strengths (TS) of carbon fibers that are less graphitized are higher than those of carbon fibers with a higher degree of graphitization if tensile moduli (TM) are almost constant.

Preparation and evaluation of isotropic and mesophase pitch-based carbon fibers using the pelletizing and continuous spinning process

2018 ◽  
Vol 48 (7) ◽  
pp. 1242-1253 ◽  
Author(s):  
Tae Hwan Lim ◽  
Moo Sung Kim ◽  
Sang Young Yeo ◽  
Euigyung Jeong
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
Large Scale ◽  
Continuous Process ◽  
Batch Process ◽  
Fiber Spinning ◽  
Mesophase Pitch ◽  
Great Length ◽  
Screw Extruder ◽  
Spinning Process

The purpose of this study is to investigate the potential of using a pelletized pitch in a continuous process for the economical preparation of large-scale pitch-based carbon fibers. The pitch was pelletized before spinning because the pitch powder can agglomerate in the feed throat of a screw extruder, which can render uniform heating difficult. Using the pelletized pitch in a single-screw extruder spinning apparatus, the pitch fiber can be spun to a great length as long as the amount of pitch pellets is sufficient. To evaluate the benefits of using pitch pellets in the continuous carbon fiber spinning process, isotropic and mesophase pitch fibers were prepared by both the conventional batch process using pitch powder and continuous process using pitch pellets. Even with a huge difference in the thermal energy used, the carbon fibers prepared using the pelletized-pitch-based continuous process had better tensile properties than those prepared using the conventional process. This suggests that the continuous process using pitch pellets has the potential to be an economical large-scale process for carbon fiber preparation.

Synthesis and Lithium Storage Performance of Sn-Co/C Composite Anode Materials for Li-Ion Battery

2011 ◽  
Vol 299-300 ◽  
pp. 516-519
Author(s):  
Shao Bin Yang ◽  
Ding Shen ◽  
Xiao Guang Wu
Keyword(s):  
Carbon Black ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Discharge Capacity ◽  
Anode Materials ◽  
Lithium Ion ◽  
Carbon Black Content ◽  
Discharge Efficiency ◽  
Charge Discharge

The Sn-Co/C composites as novel anode materials for lithium-ion batteries were prepared by solid-state sintering. The influences of carbon black content in Sn-Co/C composite on material structures and the electrochemical properties were investigated. Structure analyses show that carbon black mainly is physically mixed with CoSn phase and could inhibit the growth of grain of CoSn phase, avoid the formation of large particles and increase the specific surface area obviously. Electrochemical analyses show that the refinement of grain size or particle size could contribute to improve the discharge capacity and cycle performance, but the increasing of specific surface area could reduce the charge-discharge efficiency. When carbon black content is 6 wt.%, the discharge capacity reach its maximum, which is 275 mAh/g, the initial charge-discharge efficiency is 52.8% and the retention of discharge capacity is 72.8% after 30 cycles.

Electrochemical and Structural Properties of Si/Ni/Cu Electrode Films Fabricated with Different Methods

2006 ◽  
Vol 510-511 ◽  
pp. 266-269
Author(s):  
Gyu Bong Cho ◽  
Bong Ki Lee ◽  
Won Chul Sin ◽  
Tae Hyun Nam
Keyword(s):  
Electrochemical Properties ◽  
Structural Properties ◽  
Discharge Capacity ◽  
Amorphous Structure ◽  
Cu Substrate ◽  
Sem Observation ◽  
Cu Film ◽  
Initial Charge ◽  
Si Films ◽  
Surface Morphologies

Si film electrodes for Li micro-film batteries were fabricated on a Cu substrate and a Ni/Cu film. In the structural properties, Si film had an amorphous structure, while the crystallinity of Ni buffer film was improved after annealing. FE-SEM observation demonstrated differences in surface morphologies of Si films fabricated with different methods. In the electrochemical properties, the Ni-inserted film showed the largest initial charge and discharge capacity, and the cell with annealed Si/Ni/Cu film showed good cycleability. It is believed that the insertion of Ni film as a buffer film improved the charge and discharge capacity owing to the enhancement of adhesion between Si film and Cu substrate.

scholarly journals Heteroatom-doped core/shell carbonaceous framework materials: synthesis, characterization and electrochemical properties

2019 ◽  
Vol 43 (14) ◽  
pp. 5632-5641 ◽  
Author(s):  
Yutao Zhou ◽  
Qianye Huang ◽  
Chee Tong John Low ◽  
Richard I. Walton ◽  
Tony McNally ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Lithium Ion Batteries ◽  
Discharge Capacity ◽  
Anode Materials ◽  
Lithium Ion ◽  
Core Shell ◽  
Materials Synthesis ◽  
Framework Materials ◽  
Excellent Cycling Stability ◽  
Charge Discharge

Multiple heteroatom-doped core/shell carbonaceous framework materials showed a rapid charge–discharge capacity and excellent cycling stability, demonstrating great potential for anode materials for lithium ion batteries.

Influence of Carbon Fiber Treatment on Flexural Properties of C/SiC Composites

2018 ◽  
Vol 281 ◽  
pp. 408-413 ◽  
Author(s):  
Wei Jie Xie ◽  
Hai Peng Qiu ◽  
Ming Wei Chen ◽  
Shan Hua Liu
Keyword(s):  
Carbon Fiber ◽  
Flexural Strength ◽  
Carbon Fibers ◽  
Pyrolytic Carbon ◽  
Flexural Properties ◽  
Heat Treated ◽  
Fiber Treatment ◽  
Treated Carbon ◽  
Sic Composites ◽  
Polymer Impregnation

The purpose of this study was to investigate the influence of carbon fiber treatment on flexural properties of carbon fiber reinforced SiC matrix (C/SiC) composites. C/SiC composites were prepared by polymer impregnation pyrolysis (PIP) progress with polycarbosilane (PCS) as impregnant and carbon fiber as reinforcement. The flexural strength at room temperature of the 2D laminated composites were measured and analyzed with different carbon fiber treatment process. It was found that the flexural strength of the composites with carbon fibers coated by pyrolytic carbon was 53.5% higher than that with non-coated carbon fibers. The results also show that the flexural strength of the composites with 1600°C heat treated carbon fibers increased by 25.4% compared with the composites with non-heat treated fibers.

Synthesis and Electrochemical Properties of LiFe0.95Ti0.05Po4/(C+LiFeP2O7) Composite Material

2010 ◽  
Vol 160-162 ◽  
pp. 1588-1595
Author(s):  
Zhao Yong Chen ◽  
Jian Li Zhang ◽  
Hua Li Zhu ◽  
Wei Zhu ◽  
Qi Feng Li
Keyword(s):  
Solid Solution ◽  
Electrochemical Properties ◽  
Discharge Capacity ◽  
Protective Layer ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
X Ray ◽  
Transmission Electron ◽  
Initial Charge ◽  
State Method

A new LiFePO4-based phase composite LiFe0.95Ti0.05PO4/(C+LiFeP2O7)was synthesized by solid state method . The amorphous carbon and phosphate LiFeP2O7 consisted of the protective layer and coated the surface of the solid solution LiFe0.95Ti0.05PO4 The phosphate LiFeP2O7 was detected though XRD(X-ray diffraction)and CV(cyclic voltammetry).Morphology of the composite was observed by scanning electron microscope(SEM)and Transmission electron microscopy (TEM), it illustrated Ti4+ had been induced into the crystal lattice of LiFePO4 and formed the solid solution LiFe0.95Ti0.05PO4.The data of charge-discharge tests showed the composite had excellent electrochemical properties. Initial charge and discharge capacity of LiFe0.95Ti0.05PO4/(C+LiFeP2O7) had reached 157.9mAh/g and 155.2mAh/g at the rate of 0.1 C, respectively. At 1C, the discharge capacity of the composite remained 125mAh/g after 100 cycles.

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