Papers by Keyword: Cathode Material

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Authors: Feng Rao Lang
Abstract: This paper selects the LiNi0.5Mn0.5O2 with layer structure as the research object, and does the future research about preparation methods and synthesis conditions. LiNi0.5Mn0.5O2 cathode material was successfully synthesized by co-precipitation method. In order to explore the optimal path of LiNi0.5Mn0.5O2 material synthesized by co-precipitation method optimal path, pretreatment, calcining heat, calcining time, cooling way on the material structure. Finally find the better synthesis conditions and improve synthesis technology.
Authors: T.Q. Tan, S.P. Soo, A. Rahmat, J.B. Shamsul, Rozana A.M. Osman, Z. Jamal, M.S. Idris
Abstract: Nowadays, many researchers have been studying on the layered rock salt-type structure as cathode materials for the lithium ion batteries. LiCoO2 is the most commonly used cathode material but Co is costly and toxic. Thus, alternative cathode materials which are cheaper, safer and having higher capacity are required. Replacing Co with Ni offered higher energy density battery but it raised interlayer mixing or cation disorder that impedes electrochemical properties of batteries. This paper has reviewed some recent research works that have been done to produce better and safer cathode materials from the structural perspective.
Authors: Li Chen, Yan Ming Wang, Juan Liu, Xing Yao Wang
Abstract: A novel hydrothermal stripping technique synthesis route, in which the nickel-loaded organic phase of naphthenic acid was directly stripped by water at 140-240 °C for 2.0 h to recover nickel as hydroxide precipitates, has been firstly developed. The nickel hydroxide powders synthesized by this route was the spherical β-Ni(OH)2 and had a small particle size in the range of 20-100 nm shown by XRD and TEM test. The results of electrochemical performances show that the nanometer β-Ni(OH)2 cathode materials have much higher discharge specific capacity, excellent capacity retention and cycle performances.
Authors: Wen Qin Wang, Jun Jie Hao, Zhi Meng Guo, Qing Ye
Abstract: LiFePO4/C cathode material with particle size of 5~6 μm and tap density of 1.67 g•cm-3 was prepared based on spherical crystal FePO4•2H2O powders. The spherical crystal FePO4•2H2O powders were first prepared by a simple hydrothermal synthesis via the amorphous FePO4•2H2O solution maintained at 150°C for 12 h without any supplementary equipment. The produced LiFePO4/C powders exhibited the initial discharge capacity of 137 and 118 mAh•g-1 at 0.1 C and 0.5 C, respectively. The volumetric capacity of the spherical LiFePO4/C powders corresponded to 230 and 197 mAh•cm-3, which are remarkably higher than irregularity powders. The high-density spherical LiFePO4/C powders produced by this novel method can be considered as a very promising candidate in the high-power batteries.
Authors: Lu Zheng, Liang Bin Liu, Xiao Jing Zhou, Yu Zhong Guo
Abstract: Li (Ni1/3Co1/3Mn1/3) O2 cathode materials doped by Zn were synthesized by a co-precipitation routine, the first delithiation process of the samples with 0-4wt% of Zn doping were studied by electrochemical impedance spectroscopy (EIS) under the polarized voltage of 2.8-4.6V. The fitting results based on EIS data indicate that delithiation reactions happen within the voltage range of 3.7-4.4V ; The resistances of SEI film and charge transfer are both decreased significantly, whereas Li+ diffusion ability through layered crystalline lattice is improved largely with the increase of zinc doping from 0 to 4wt%.
Authors: Mohd Sazwan Affendi Rasiman, Fadhlul Wafi Badrudin, Muhamad Kamil Yaakob, M.F.M. Taib, Ab Malik Marwan Ali, Muhd Zu Azhan Yahya, Oskar Hasdinor Hassan
Abstract: First-principles calculations based on the DFT approximated by GGA-PBEsol scheme has been utilized to predict the structural and electronic properties of Li2MnP2O7 and possible delithiated Li2-xMnP2O7 (x=1,2) configurations. Our results show that the approximation provided more reasonable predictions on the structural consistent with experiments. The calculated voltage profile underestimate the experimentally observed redox potential. Density of States (DOS) results reveals the insulator behavior of Li2MnP2O7.
Authors: Guan Min Li
Abstract: Polymer electrolyte organic polymer as the main matrix, poor mechanical properties, in addition, the ion transfer is mainly in the amorphous regions completed and the polymer electrolyte composite polymer generally has a strong ability to crystallize, thus greatly suppressed ion transmission. People try by the incorporation of different types and contents of the filler to improve the mechanical properties of the polymer electrolyte, lower crystallinity and increase the ionic conductivity. Various inorganic nanoparticles are the most common type of doping filler.
Authors: Peng Li, Sheng Xiang Bao, De Zheng Zhang, Li Bo Zhuang, Li Li Ma
Abstract: The study of the secondary electron composition contrast imaging method have been developed with a conventional scanning electron microscope (SEM) equipped with ultra-thin window energy dispersive X-ray spectrometer (EDS). On the basis of the study of the principle of secondary electron emission, secondary electron composition contrast imaging method has been investigated, and the ranges of its application were also discussed. This method was applied in the microstructure studies on cathode materials of TWT (traveling wave tube). The results showed that, compared with backscattered electron image, the secondary electron image could also reveal composition contrast well in certain conditions. Furthermore, the resolution of secondary electron composition contrast image is higher. In some cases, the secondary electron image could distinguish impurities which might bring wrong results. In the microstructure studies on cathode materials of TWT, compared with backscattered electron image, secondary electron composition contrast imaging method is reasonable and practicable.
Authors: Jie Zhao, Jiang Fu, Yong Fu, Yu Na Zhao, Yong Chang Ma
Abstract: Sr, Ca and Fe doped cathode materials Ln0.7Sr0.2Ca0.1Co0.7Fe0.3O2.85 (LnSCCF, Ln=La, Pr and Nd; abbreviated as L-72173, P-72173 and N-72173) were synthesized by microwave sintering (MWS) techniques. The formation process, phase structure and composition were characterized using TG/DTA, XRD and EDS. The thermal expansion behavior of the samples was analyzed in the range of 20-950 °C by thermal dilatometer. The electrical conductivity of the samples was measured with DC four-terminal method from 25 to 900 °C. The X-ray diffraction shows that the samples exhibit a single phase with rhombohedral or cubic perovskite structure after sintered at 1200 °C for 20 min. The electrical conductivity of the samples increases with temperature up to a maximum, and then decreases gradually at higher temperature owing to the creation of oxygen vacancies. The small polaron hopping is regarded as the conducting mechanism (T 550 °C). L-72173 has higher mixed conductivity ( >300 S·cm-1) in 550-800 °C. The average TECs of L-72173, P-72173 and N-72173 are 1.389× 10-5 K-1, 1.417 × 10-5 K-1 and 1.416 × 10-5 K-1 in the range of 25-800 °C, respectively. They are thermally matched to the GDC better than the YSZ and SDC.
Authors: M. Yoshio, Hajime Noguchi, S. Ishimoto
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