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Preparation And Application Of Ternary Layered Carbide Ti2SC

Posted on:2016-10-16Degree:MasterType:Thesis
Country:ChinaCandidate:Y C WangFull Text:PDF
GTID:2271330464952700Subject:Physical chemistry
Abstract/Summary:PDF Full Text Request
The ternary compound, Ti2SC, is a member of a class of materials that are now widely referred to as the Mn+1AXn phases. It is a new material which combine the merits of both metals and ceramics.Therefore, Ti2SC can be a promising material with a broad application prospect. According to the theoretical calculation, the two-dimensional ultra-thin MAX phase materials have more excellent performance than the bulk materials. Ti2SC materials were successfully synthesized by Self-Propagation Reaction from the mixed powders of Ti, S, C, Al. On one hand, fully dense Ti2SC materials were prepared using the as-received powders as raw materials by plasma sintering at different temperature and under various holding time. The microstructure as well as mechanical properties of Ti2SC were investigated. On the other hand, on the basis of this study nano Ti2SC material were preparation. The application of nano Ti2SC and nano Ti2SC modified by graphene as anode material in lithium ion batteries was investigated.Ti2SC materials were successfully synthesized by Self-Propagation Reaction, in which, the mixed powders of Ti, S, C, Al were used as raw materials in an atomic ratio of 2.0:1.0:1.0:0.1, respectively. The purity of Ti2SC was estimated up to 92.44% by lvalue method. Appropriate amount of Al additives can be formed the liquid phase as soon as possible in the reaction system. Meanwhile accelerating the diffusion of Ti and promoting the formation of an intermediate phase, so as to promote the synthesis of Ti2SC. The prepared Ti2SC was as a raw material, for 4h in a ball mill of 400r/min. Then tacking CH2COOH as solvent, and with ultrasonic treatment about 240min, the nano Ti2SC thin layer was successful prepared, nanosheet diameter 100-300nm.The fully dense Ti2SC materials were prepared using the as-received powders as raw materials by spark plasma sintering at 1250℃ for 5 min. The microstructure as well as mechanical properties of Ti2SC were investigated. The sample exhibited excellent mechanical properties, and its density, relative density, Vichers’hardness and fracture toughness were 4.57 g/cm3,98.28%,8.61 GPa and 5.81 MPa-m12, respectively. It can be seen from its fractured surface that Ti2SC was composed of both laminar and lath-like grains, suggesting a self-toughning performance.As a new lithium-ion anode material, the nano Ti2SC material has superior performance stability, cycle performance and rate performance. In the 100mA/g,200mA/g,400mA/g, 800mA/g and 1600mA/g current density, respectively, the stable capacity reached 175mAh/g, 170mAh/g.133mAh/g. 113mAh/g, and 90mAh/g. With the virtue of its large specific surface area and unique structure, its performance was significantly better than the micron level T12SC material.What’s more, compared to the nano Ti2SC, the nano Ti2SC/RGO materials showed superior behavior with higher capacity, better rate performance and long lifetime. In the current density of 100mA/g,200mA/g,400mA/g,800mA/g and 1600mA/g, the stable capacity reached 413mAh/g,370mAh/g,310mAh/g,266mAh/g and 212mAh/g, respectively.
Keywords/Search Tags:high temperature self-propagating synthesis, nano Ti2SC, mechanical properties, spark plasma sintering, lithium-ion battery
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