| It has been becoming very important to improve the capability of carbon cathode material, and father to improve the capacity of lithium ion secondary batteries. Preparation of CaAl2Si2 cathode material, a new sandwich material, and its discharge properties for lithium ion secondary batteries have been systematically studied in present paper with X-ray Diffraction, Rietveld Resolution and Direct Current Tow-terminal Measurement of Electronic Conductivity (DCTMEC).In the preparation of CaAl2Si2, Al powder and CaSi2 are mixed in different mol rates and shaped by CIP (Cold Isostatic Pressing) method, then sintered at different sintering temperatures, heating rates, holding times and heat-treatments. The optimum parameters for preparation of CaAl2Si2 have been concluded as follows: the sintering temperature is 1373 K, heating rate 500 K h-1 and molar ratio of Al: CaSii- 2: 1; On these conditions, goodness-of-fit indicator of metrical value and calculating value is 1.2236 after Rietveld resolution analysis. This means that the experimental results are reliable to those obtained by the theoretical calculations; The DCTMEC result shows that CaAl2Si2 is a semiconductor and an ideal electrode material, having higher conductivity than other electrode material; Discharge results with anode of CaAl2Si2 and cathode of lithium indicate that the best electrolyte is the mixture of solute of LiC104 and solvents of ethylene carbonate (EC) and diethyl carbonate (DEC). On this condition, discharge capability of CaA^Sii has been as high as 210mA h g-1, and its mol discharge capability is 7.9 times as that of carbon cathode material. This means that lithium takes on high absorbing density; According to Faraday's law, lattice-intercalating ways of lithium is that one lithium atom intercalate in each of CaAl2Si2 crystal lattice, mainly on the face of (0 0 3).The results above are significant both theoretically and applicably to develop new sandwich CaAl2Si2 cathode materials.
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