Guang Chuan Liang

Preparation and Modification of Nano-Li4Ti5O12 Anode Material

The spinel nano-Li4Ti5O12 was prepared by hydrothermal reaction method. The crystal structure, morphology and charge/discharge capacities were characterized by powder X-ray diffraction and Scanning electron microscopy and program-controlled tester respectively. It showed that lithium titanate synthesized by the direct hydrothermal method has a uniform particle size distribution of about 100nm in cubic shape. Investigated the influence of different carbon sources on the structure and electrochemical properties. It was found that the discharge capacities could reach 172.2, 159.8, 156.2 and 148.3mAh/g at 0.2C, 1C, 2C and 5C rates, respectively.

Enhanced Electrochemical Properties of LiFePO4/C Cathode Material by Metal Oxide Coating

LiFePO4/C composite cathode material prepared by carbothermal reduction method was coated by metal oxide MnO2, Al2O3, CuO, respectively, by a chemical precipitation method. The effects of metal oxide coating on the structure and electrochemical performance of LiFePO4/C composites were systematically investigated. The structure and morphology of the samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the electrochemical properties were evaluated by constant-current charge/discharge cycling tests. It is found that the coating of metal oxide could greatly improve its high-rate dischargeability and cycling performance. The LiFePO4/C cathode material coated by MnO2 exhibits a specific discharge capacity of 118.5 mAh/g at 3C rate, much higher than the uncoated sample (95.1 mAh/g), with a capacity degradation rate of only 6.3 % after 250 cycles at 3C rate.

University Teaching of Effective Quality Engineering Based on the Compound Technological Talents Training

The compound technological talents training of power source and ecomaterials (PSEM) is one of the most important development strategies for constructing a resource-saving and environment-friendly society. Effective Quality Engineering (EQE), using the engineering method to solve the quality problem of a new product, is a basic theory method. In this paper, the quality design method of EQE was integrated into the teaching of inorganic non-metallic professional courses. On this basis, the teaching mode of initiative introduction and requirement assisted reading was discussed. After six years of teaching practice, it is proved that the basic theory of EQE and the new teaching ways can be effectively applied to the training of compound technological talents of PSEM. Especially, through this method, the designed materials exhibit optimal quality.

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

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.

Enhanced Electrochemical Performance of Li4Ti5O12/C Composite Prepared by Solid-State Method

Phase pure Li4Ti5O12/C composite was synthesized by solid-state method using Li2CO3 and anatase TiO2 as starting materials, and glucose, citric acid and oxalic acid as carbon sources, respectively. The effects of different carbon sources and various glucose amounts on the microstructure and electrochemical properties were systematically investigated. The as-prepared samples were characterized by means of XRD, SEM and particle size analysis. The electrochemical properties were investigated in terms of constant-current charge/discharge cycling tests. The results showed that the Li4Ti5O12/C composite with 2wt% glucose exhibited the optimal electrochemical performance with a specific discharge capacity of 190.8mAh/g at 0.2C rate. The discharge capacity could still reach 151.0mAh/g after 80 cycles at 1C rate, exhibiting excellent cycling performance.

Synthesis and Electrochemical Performance of LiFe1-xMnxPO4/C Cathode Material

Olivine LiFe1−xMnxPO4/C composites were prepared by high temperature solid phase method using MnO2, NH4H2PO4, Li2CO3, FeC2O4•2H2O, glucose as the starting materials. XRD, SEM and constant-current charging/discharging tests were used to study the structure and electrochemical properties of the material. The result showed that when x=0.2 the material exhibited the optimal electrochemical performance, with a higher specific energy of 484.94 Wh/kg.

Research and University Education in Ecological Environment Functional Materials in China

The research progress and university education situation in ecological environment functional materials (EEFMS) in China were analyzed. A new subject of EEFMS involved in many subject knowledge, such as materials, energy and environment, has come into being due to the rapid development of the advance industry of energy and environment materials in the last decade, as well as a serial of new industries of micro-environment control functional materials, and so on. At the same time, the university education was accelerated in the direction of the research in EEFMS.

Kinetics of LiFePO4 Cathode Material Prepared by Carbothermal Reduction Method

The kinetic parameters of each stage of LiFePO4 material prepared by carbothermal reduction method were calculated using the Doyle-Ozawa and Kissinger methods. The results showed that the final maximum activation energy of LiFePO4 material was 189.26kJ/mol. The peak shape index, response factor, frequency factor and rate equation of each stage were calculated using the Kissinger methods.

Research Progress in Ionic Functional Materials used for Energy Saving and Emission Reduction

The application of ionic functional materials for energy saving and emission reduction in China was introduced in this paper. Firstly, the application of mine materials in the field of architectural energy saving, including heat insulation materials, combustion energy saving materials and enhancing heat emission materials,etc, was introduced. Secondly, the application of ionic functional materials in the field of automobile energy saving was introduced. The product technology of promoting energy saving through activating fuel, air and cycling water by activative bed technology was also introduced, aimed at industry boiler. Finally, the application in battery field of lithium-ion storage materials, including natural pyrite and lithium iron phosphate materials was introduced.

Enhancement of Electrochemical Performance of Li4Ti5O12/C Composite Prepared by Sol-Gel Method

Phase pure Li4Ti5O12/C composite was synthesized by sol-gel method using lithium acetate CH3COOLi•2H2O and tetrabutyl titanate [Ti(OC4H9)4] as starting materials, oxalic acid as chelating agent and sucrose as an additional carbon source. The as-prepared samples were characterized by means of TG-DTA, XRD and SEM. The electrochemical properties were investigated in terms of constant-current charge/discharge cycling and high-rate dischargeability. SEM analysis indicated that the prepared Li4Ti5O12/C composite using sucrose and oxalic acid as carbon source showed a spongy nano-particle aggregate structure, with average nano-particle size of 80-100 nm. Electrochemical results showed that the Li4Ti5O12/C composite prepared in the presence of sucrose exhibited better electrochemical performance with specific discharge capacities of 204.7, 171.6, 155.3 and 154.6 mAh/g at 0.2C, 1C, 2C, and 5C rates, respectively. And the discharge capacity could still reach 143.9mAh/g after 80 cycles at 1C rate, exhibiting excellent cycling performance.