Chemical Modification of Carbon Materials and Transport Properties of the Resulting Compounds

碳1s光谱被确定为钾插层石墨成分K/C的函数。随着K/C的增加，C1s能谱向高能量方向移动并展宽。费米能级随K/C的增加而增加，这是钾离子向碳离子π带电荷转移的结果。CsC_<24>等碱金属-石墨插层化合物可以在其层间纳米空间内容纳多种分子。了解碱金属离子与穿透分子之间的相互作用是非常有趣的。结果表明，CsC_<24>体系的电导率变化明显，吸附温度对CsC_<24>-C_2H_2体系电导率变化的影响较大。另一方面，CsC_<24>的电导率变化小于10%，且CsC_<24>-C_2H_4的温度效应较小。从Cs离子可以与C_2H_2的π电子相互作用，而不能与C_2H_4的π电子相互作用的角度讨论了这些结果。测定了石墨化程度对钾插层碳材料电导率、磁阻和霍尔系数的影响。石墨化良好的材料的导电性和磁阻值较大。对于石墨化程度较差的材料，即使插入钾元素，其电导率的温度依赖关系也不会转变为金属依赖关系。

Carbon 1s spectra were determined as a function of the composition, K/C,for potassium intercalated graphite. The C1s spectra shifted towards higher energy and broadened with the increase of K/C.The shift was explained on the basis of the fact that the Fermi level shift increases with the increase of K/C as a result of the charge transger from potassium to carbon pi bands.Alkali metal-graphite intercalation compounds such as CsC_<24> can accomodate various molecules in its interlayr nano-spaces. It is very interesting to know the interaction between alkali metal ions and the penetrating molecules. It was found that the electrical conductivity of CsC_<24> changed remarkably and the effect of sorption temperature on the electical conductivity change was large for the system CsC_<24>-C_2H_2. On the other hand, the change of the electrical conductivity of CsC_<24> was less than 10%, and the temperature effect was small in the case of CsC_<24>-C_2H_4. Those results were discussed from the viewpoint that Cs ions can interact with pi electrons of C_2H_2, but not for C_2H_4.Effect of the degree of graphitization on the electrical conductivity, magnetoresistance and Hall coefficient of potassium intercalated carbon materials was also determined. Large values of the electrical conductivity and the magnetoresistance were observed for well graphitized material. For poorly graphitized materials, the temperature dependence of the electrical conductivity did not change to metallic one even if the intercalation of potassium took place.