Papers by Keyword: Anode

Abstract: In the present paper, a composite containing mixed oxides of tin and lead has been synthesized by the method of pulsed high-voltage discharge. Material was characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis and transmission electron microscopy. The composite consists of SnO₂ and PbO particles with an average size of ~350 nm, and SnPb₂O₄ nanowhiskers with size of 100 nm in diameter and few microns in length. The electrochemical performance of nanocomposite as a potential anode of lithium-ion battery has been investigated by the cyclic voltammetry and galvanostatic charge/discharge test in the potential range of 3.0–0.005 V. The reversible capacity of 821 mA·h/g was realized after 5-fold cycling at a current density of 100 mA/g. It was established that further cycling of the material is accompanied by a dramatic capacity fade: only 13 % of the initial capacity was obtained already after 10 cycles. The observed degradation in performance of nanocomposite results from its inability to compensate large lithiation/delithiation-induced volume expansion.

Abstract: Lithium Titanate (LTO) is one of the anode materials that has good performance because of its unique properties, which is zero-strain. In this study, LTO was synthesized using the sol-gel method and mechanochemical hydrothermal with LiOH as the source of lithium-ion. Silicone oxycarbide (SiOC) is a ceramic material synthesized through a simple pyrolysis process of silicone oil precursors. Carbon used in this study is a carbon activated process so that activated carbon is obtained with a large pore size. The addition of activated carbon to the LTO is done during the sol-gel process, while the addition of SiOC to LTO-C is performed during the slurry making process. SEM-EDS shows the extent of the elements in the sample where Ti, F, Si, O, and C are present. Also, SEM-EDS characterization shows an increase in the amount of carbon in each sample. XRD shows the presence of the LTO spinel phase and impurity phases such as TiO₂ rutile and anatase, and Li₂TiO₃. In EIS performance testing, low resistivity expresses high conductivity. In this research, high conductivity is owned by LTO-1% C/SiOC. In addition, CV and CD performance tests were performed where the highest specific capacity was obtained in the LTO-5%/SiOC samples.

Abstract: To obtain the high specific capacity anode for Lithium-ion battery with stable performance is conducted by synthesizing a composite anode of ZnO-nanorods (ZnO-NR) and as a matrix is the activated carbon (AC). In this study, ZnO-NR synthesized a process that uses basic materials hexamethylenetetramine (HMTA) and zinc oxide. Activated carbon has been activated because it has high porosity and good electrical conductivity properties. Variable used is the percentage of ZnO-NR, which is 30wt%, 40wt%, and 50wt%. Characterization of the samples was examined using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Brunauer–Emmett–Teller (BET). The battery performance of the samples was obtained by Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV), and Charge-Discharge (CD) testing after being assembled into coin cell batteries. This study discusses the effect of adding activated carbon to ZnO NR composites. The results showed that the ZnO-NR30/AC has the highest specific capacity of 270.9 mAh g^-1. According to Brunner-Emmet-Teller (BET) test, the largest surface area was 631.685 m2 g^-1. Electrochemical performance is the best obtained by ZnO-NR30/AC.

Abstract: Nowadays, there is an increasing of the demanding in high energy density lithium-ion batteries (LIBs) due to the growing of energy storage needs for electronic vehicles and portable devices. Silicon (Si) and Tin (Sn) are the promising anode materials for LIBs due to their high theoretical capacity of 4200 mAh/g and 994 mAh/g. Moreover, Si can be derived from rice husk which is the main agricultural product in Thailand. However, the using of Si and Sn encounters with the huge volume expansion during lithiation and delithiation process. To alleviate this problem, Nitrogen-doped graphene (NrGO), carbon supporter, is used as composite with these metals to buffer the volume change and increase the electrical conductivity of composites. This work aims to synthesis Si/NrGO and SiSn/NrGO nanocomposites and Si used in these composites is derived from rice husk. All products were characterized by X-rays diffraction (XRD), Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. XRD results showed that the composites contained phases of Si, Sn and carbon. The electron microscopy techniques were the main part to clarify the morphology and distribution of Si and Sn particles on NrGO. SEM and TEM results confirm that there were small sized particles of Si and Sn dispersed and covered on NrGO surface. Furthermore, the electrochemical properties of prepared composites were measured to confirm their efficiency as anode materials in lithium-ion batteries by coin cell assembly. The composite with 10 percent Si and 10 percent Sn on NrGO could deliver a high capacity around 480 mAh/g over 100 cycles and expected to use as anode materials in the next generation lithium-ion batteries.

Abstract: The 21700 battery is a standard battery used by Tesla vehicles in the United States. It has the advantages of high energy density ratio, high output, low cost and high safety factor. The demand for 21700 battery is gradually increasing on the market. In order to meet the needs of new energy vehicles, the 21700 battery uses copper tab as the anode, which can minimize the internal resistance and improve the charge and discharge efficiency. However, the material of the battery case is steel, and the melting point of the steel is 452°C higher than that of copper. It is difficult to solder firmly using the traditional resistance welding process. In this paper, using TRIZ theory, through the causal analysis, technical conflict, material-field, physical conflicts and other tools, the 21700 battery anode resistance welding problem is analyzed in detail, and based on the analysis results to propose solutions: punching out the pitting on the tab forming a projection welding; inserting metal tungsten in the copper welding head; changing the welding pin head from the platform to the curved surface; introducing nitrogen gas. Under the premise of constant material and no increase in cost, the problem of poor welding of the anode and the battery case can be effectively solved.

Abstract: Considering the S-vacancy defect in single-layer MoS₂, the metal doped including Fe-, Co-, Cu-, Zn-, doped specimens in MoS₂ single-layer and their effect of the adsorption and diffusion of Li on the MoS₂ single-layer were investigated by Density Functional Theory (DFT). Under Mo-rich condition, the Fe-, Co-, Cu-, Zn-doped specimens by substitution of S atom have smaller formation energy than those under S-rich condition. For doped MoS₂ single-layer, lithium donates electron to doped specimens, making the band level of the doped specimens downward into the valence band and the Fermi energy level further upward. The Li ion has positive charge, the ion adsorptive property was enhanced because of strong coulomb interaction. These are confirmed by the large adsorption energies (-1.11 ~ -0.44 eV). The diffusion energy barriers except for the path closest doped specimens by substitution of S atom are ~ 0.25, which are similar to that of pristine one. Above all, the metal doped by substitution of S atom MoS₂ single-layer are promising anode materials of LIBs.

Abstract: In this paper, carbon coated spherical Mn₃O₄ was prepared by decomposition of spherical MnCO₃ and sucrose. The results of XRD and SEM showed that Mn₃O₄/C composites are sphere-like with good crystallinity, and its diameter is about 1um. It could deliver a reversible charge capacity of 848.7 mA h g^-1 at the current density of 162.3 mA g^-1, and the specific discharge capacity is still have 441 mA h g^-1 at a high current density of 649.4 mA g^-1 exhabiting good rate performance. The excellent performance of the spherical Mn₃O₄/C composites could be attributed to its unique architecture which provides fast lithium ion and electron transportation as well as accommodates the large volume change of transition metal oxides during conversion reactions.

Abstract: In the photovoltaic industry a total of 100,000 tons of silicon is lost as waste per year. This waste is originating from several cropping and sawing steps of the high purity silicon blocks and ingots during the solar cell wafer production, resulting in a silicon containing suspension. Among different approaches to recycle the silicon from this waste is the utilization of hydrocyclones, which can be used to separate or classify particles by weight and size. In this work the use of a hydrocyclone was evaluated to upgrade the silicon fraction from a typical sawing waste. A potential field of use for the recycled silicon particles might be as anode material for next generation lithium ion batteries.

Abstract: In this study, Si@C/Graphite composite anodes were synthesized through spray drying and pyrolysis using silica, artificial graphite, and two kinds of organics (phenolic resin or pitch). The Si@PR-C/Graphite exhibits enhanced electrochemical performance for lithium-ion batteries. The first charge-discharge specific capacity is 512.8mAh/g and 621.8mAh/g, respectively, the initial coulombic efficiency is 82.5% at 100mA/g, and its capacity retention rate reached as high as 85.4% with the capacity fade rate of less than 0.18% per cycle after 85 cycles. The Si@PI-C/Graphite also presents excellent discharge specific capacity of 702.8mAh/g with the capacity retention rate of 76.9% after 30 cycles. Mechanisms for high electrochemical performances of the Si@C/Graphite composite anode are discussed. It found that the enhanced electrochemical performance due to the formation of core/shell microstructure. These encouraging experimental results suggest that proper organic carbon source has great potential for improvement of electrochemical properties of pure silicon as anode. Key words:lithium-ion batteries; anode; Si@C/Graphite composite; electrochemical performance

Abstract: The article is devoted to the study of the impact of technological features of the anode paste production on one of the technical-and-economic indices – its consumption. It is shown that the prior thermal preparation significantly affects the quality characteristics of pitch and petroleum cokes. The comparison of pitches of foreign and homeland producers revealed the advantage of the last because of their small ash content and the lowered content of sodium. Granulometric composition of the dry mix is determined on the basis of different coke brands. They are close to the concentrations of fractions regulated by the technology of production of the anode paste. The conducted semi-industrial tests were in accordance with the laboratory studies and confirmed the fact of reducing the consumption of the anode paste when using the petroleum coke as a filler.