英语学术写作 作业二.doc

英语学术写作 作业二中英文文献摘要的对比 MG1134034 杨华珍Native(1) High rate performance of Li1.05Ni1/3Co1/3Mn1/3O2 cathode materialsIntroduction提出这篇文章研究的目的是要制备高性能的三元正极材料 prepared using sol-gel (SG) and co-precipitation (CP) methods were investigated. Scanning electron microscopy results showed that the particle sizes of the materials prepared by SG and CP methods were 300400 nm and 12 m, respectively. Rate capability tests were performed and compared on these cathode materials with same electrode loading (7 mg cm-2). Li1.05Ni1/3Co1/3Mn1/3O2 cathode with smaller particle size (SG-nano) demonstrated higher discharge capacity than that of the cathode with larger particle size (CP-micro) at different Crates. However, upon extended cycling at 1C and 8C, CP-micro showed better capacity retention when compared to that of SG-nano. CP-micro exhibited 95 and 91% where as SG-nano exhibited only 87 and 76%, respectively, at 1C and 8C after 50 cycles. Methods详细阐述了如何解决实现这个目标（溶胶凝胶法，共沉淀法），数据，研究方法The results showed that the use of nanosized materials was advantageous for obtaining a better rate capability where as the use of microsized materials was benecial for better capacity retention during extended cycling at high C-rates.Results概括一下自己的结果(2) One of the challenges for improving the performance of lithium ion batteries to meet increasingly demanding requirements for energy storage is the development of suitable cathode materials. Cathode materials must be able to accept and release lithium ions repeatedly (for recharging) and quickly (for high current). Transition metal oxides based on the _-NaFeO2, spinel and olivine structures have shown promise, but improvements are needed to reduce cost and extend effective lifetime. In this paper, recent developments in cathode materials for lithium ion batteries are reviewed. Introduction提出研究高性能正极材料的目的，层状结构在快速从放电的优势所在This includes comparison of the performance characteristics of the promising cathode materials and approaches for improving their performances.Discussion讨论此种材料对锂电行业未来发展的贡献（即，提高电性能）(3) In this paper we report the study of a high capacity Sn-C nanostructured anode and of a high rate, high voltage LiNi0.45Co0.1Mn1.45O4 spinel cathode.Introduction提出这篇文章研究的目的是要制备高性能的三元正极材料 We have combined these anode and cathode materials in an advanced lithium ion battery that, by exploiting this new chemistry, offers excellent performances in terms of cycling life, i.e., ca. 100 high rate cycles, of rate capability, operating at 5C and still keeping more than 85% of the initial capacity, and of energy density, Methods详细阐述了如何解决实现这个目标（一种新的化学方法），数据，研究方法expected to be of the order of 170 Wh kg-1.Results概括一下自己的结果,希望发电比容率为170Wh kg-1 These unique features make the battery a very promising energy storage for powering low or zero emission HEV or EV vehicles.Discussion讨论此种三元正极材料（即，在，混合动力上的贡献）(4) Phosphate materials are being extensively studied as lithium-ion battery electrodes. In this work, we present a high through put into analysis of phosphates as cathode materials. Capacity, voltage, specific energy, energy density, and thermal stability are evaluated computationally on thousands of compounds. The limits in terms of gravimetric and volumetric capacity inherent to the phosphate chemistry are determined. Voltage ranges for all redox couples in phosphates are provided, and the structural factors influencing the voltages are analyzed. Introduction提出磷酸盐在锂离子正极材料中的应用，作者研究的目的We reinvestigate whether phosphatematerials are inherently safe Methods详细阐述了如何解决实现这个目标，研究方法and find that, for the same oxidation state, oxygen release happens thermodynamically at lower temperature for phosphates than for oxides. Results概括一下自己的结果，低温下氧化态These findings are used to recommend specific chemistries within the phosphate class and to show the intrinsic limits of certain materials of current interest (e.g., LiCoPO4 and LiNiPO4).Discussion讨论此种三元正极材料的贡献）(5) LiCo2/3Ni1/6Mn1/6O2 layered oxide was synthesized by the combustion method that led to a crystalline phase with good homogeneity and low particles size. Methods详细阐述了如何解决实现这个目标，研究方法The structural properties of the prepared positive electrode material were investigated by performing XRD Rietveld refinement. Practically no Li/Ni mixing was detected evidencing that the studied compound adopts almost an ideal _-NaFeO2 type structure. Introduction提出这种三元正极材料在锂离子正极材料中的应用，作者研究的目的The Li|LiCo2/3Ni1/6Mn1/6O2 cell showed a discharge capacity of 199mAhg1 when cycled in the 2.74.6V potential range while the best cycling performances were recorded when the upper cut off is fixed at 4.5 V. Structural changes in LixCo2/3Ni1/6Mn1/6O2 with lithium electrochemical de-intercalation were studied using X-ray diffraction. Methods详细阐述了如何解决实现这个目标的数据具体方法This study clearly shows the existence of a solid solution domain in the 0.1 x 1.0 composition range while for x = 0.1,Results概括一下自己的结果 a new phase appears explaining the decrease of the electrochemical performance when the cell is cycled at high upper cut off voltage.Discussion讨论此种三元正极材料的贡献(合成新相)(6) A series of mixed metal hydroxide (NixMnxCo(12x)(OH)2) precursors for the preparation of lithiated mixed metal oxides (LiNixMnxCo(12x)O2) were prepared using a novel coprecipitation approach based on the thermal decomposition of urea.Introduction提出这种三元正极材料，作者研究的目的 Three different methods were used to achieve the temperature required to decompose urea and subsequently precipitate the hydroxides. The first two methods consisted of either a hydrothermal or microwaveassisted hydrothermal synthesis at 180 C and elevated pressures. The final method was an aqueous reflux at 100 C. A complete series (x=0.000.50) was prepared for each method and fully characterized before and after converting the materials to lithiated metal oxides (LiNixMnxCo(12x)O2). We observed the formation of a complex structure after the coprecipitation of the hydroxides. Methods详细阐述了如何解决实现这个目标（本文用了3种不同的方法）Scanning electron micrographs images demonstrate that the morphology and particle size of the hydroxide particles varied significantly from x=0.000.50 under hydrothermal synthesis conditions. There is also a significant change in particle morphology as the urea decomposition method is varied. Results概括一下自己的结果The X-ray diffraction profiles of the oxides synthesized from these hydroxide precursors all demonstrated phase pure oxides that provided good electrochemical performance.Discussion讨论此种三元正极材料的贡献(高的充放电循环性能)(7) With an aim to suppress the huge irreversible capacity loss encountered in high capacity layered oxide solid solutions between Li2MnO3 and LiMO2 (M = Mn, Ni, and Co), layered LiLi0.2Mn0.54Ni0.13Co0.13O2V2O5 composite cathodes with various V2O5 contents have been investigated. The irreversible capacity loss decreases from 68 mAh/g at 100% LiLi0.2Mn0.54Ni0.13Co0.13O2 to 0 mAh/g around 89 wt.% LiLi0.2Mn0.54Ni0.13Co0.13O211 wt.% V2O5 as the lithium-free V2O5 serves as an insertion host to accommodate the lithium ions that could not be inserted back into the layered lattice after the first charge.Methods详细阐述了如何解决实现这个目标,数据，研究方法 The LiLi0.2Mn0.54Ni0.13Co0.13O2V2O5 composite cathodes with about 1012 wt.% V2O5 exhibit an attractive discharge capacity of close to 300 mAh/g with little irreversible capacity loss and good cyclability.Results概括一下自己的结果(8) Various compositions of the xLi2MnO3yLiNi1/3Co1/3Mn1/3O2zLiNiO2 electrode system were synthesized using metal oxide precursor by adopting co-precipitation method. Introduction提出这种共沉淀法在制备此种三元正极材料在锂离子正极材料中的应用，作者研究的目的XRD revealed that the prepared cathode materials possess _-NaFeO2 structure with R3m space group. Scanning electron micrographs demonstrated the morphology of all the synthesized samples, wherein spherical agglomerates with size of 510_m have been acknowledged. Among the tested samples, LiLi0.18Ni0.220Co0.120Mn0.480O2 shows the excellent capacity retention (95.6%) in the voltage range of 2.04.6V and the better rate capability than the other samples. But, on the other hand, LiLi0.20Ni0.133Co0.133Mn0.534O2 (x = 0.6, y = 0.4 and z = 0.0) shows the highest discharge capacity. However, the capacity retention of the material at 50mAg1 is lower than that of LiLi0.18Ni0.220Co0.120Mn0.480O2. Furthermore, the capacity retention at 1250mAg1 is only 42.6% of the capacity obtained at 20mAg1.Methods详细阐述了如何解决实现这个目标,数据，研究方法(9) The layered oxide cathode material LiMO2, where M=Ni0.9-yMnyCo0.1 and 0.45 e y e 0.60, was synthesized by a coprecipitation method. Introduction提出这种共沉淀法在制备此种三元正极材料在锂离子正极材料中的应用，作者研究的目的X-ray diffraction analysis shows that the maximum manganese content in the stoichiometric material, i.e. with Li:M = 1, cannot exceed 50%; otherwise, a second phase is formed. Rietveld refinement reveals that increasing manganese content suppresses the disorder between the lithium and nickel ions. Magnetic measurements show that part of theMn4 ions in the manganese rich compounds is reduced toMn3 ; this results in a larger hysteresis loop due to the increased magnetic moment of the resulting ferrimagnetically ordered clusters. LiNi0.4Mn0.5Co0.1O2 and LiNi0.45Mn0.45Co0.1O2 show similar electrochemical capacities of around 180 mAh/g (between 2.5 and 4.6 V at 0.5 mA/cm2) for the first discharge. Methods详细阐述了如何解决实现这个目标,数据，研究方法However, subsequent cycling of LiNi0.4Mn0.5Co0.1O2 results in faster capacity loss and poorer rate capabilityResults概括一下自己的结果 indicating that manganese rich compounds, with Li:M=1:1, are probably not suitable candidates for lithium batteries.Discussion讨论此篇文章研究结果的贡献（Li：金属原子=1:1时并不合适做正极材料的配比）(10) The surface of LiNi1/3Co1/3Mn1/3O2 (LNMCO) particles has been studied for material synthesized at 900 C by a two-step process from a mixture of LiOHH2O and metal oxalate (Ni1/3Co1/3Mn1/3)C2O4 obtained byco-precipitation. Samples have been characterized by X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), Raman scattering (RS) spectroscopy, and magnetic measurements.Methods详细阐述了如何解决实现这个目标,数据，研究方法We have investigated the effect of the heat treatment of particles at 600 C with organic substances such as sucrose and starch. HRTEM images and RS spectra indicate that the surface of particles has been modified. The annealing does not lead to any carbon coating but it leads to the crystallization of the thin disorderedlayer on the surface of LiNi1/3Co1/3Mn1/3O2. The beneficial effect has been tested on the electrochemical properties of the LiNi1/3Co1/3Mn1/3O2 cathode materials. The capacity at 10C-rate is enhanced by 20% for post-treated LNMCO particles at 600 C for half-an-hour.Results概括