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As can be developed dwindling energy , coal , oil, natural gas extraction and processing caused environmental pollution ( air pollution, acid rain , global warming , etc. ) become increasingly serious , develop clean and environmentally friendly new energy imminent. Thermoelectric conversion device as compact structure, no moving parts, work without noise , long life, does not fail safe , easy auto maintenance, pollution, etc., to stimulate people's enthusiasm for research . As a core part of thermoelectric thermoelectric materials naturally become the focus of the study , the paper work to Ca 3 Co 4 O 9 thermoelectric materials object of study, through different doping to improve its thermoelectric properties , has been initially achieved good results. In this thesis, the sol - gel method Ca 3 Co 4 O 9 and doping different ions (Na , Ag , La 3 ) thermoelectric materials, through TG-DTA, IR, XRD, SEM and thermoelectric performance testing of samples studied architecture , morphology and thermoelectric properties , and the effects of different ions doped Ca 3 Co 4 O 9 structure and thermoelectric properties . The results showed that the use of sol - gel preparation of Ca 3 Co 4 O 9 thermoelectric material samples prepared with other methods , compared with dense internal structure and good thermal properties. Doped with different ratios according to various metal ions (Na , Ag , La 3 ) , the optimization of the carrier concentration of the sample , thermoelectric properties of the sample have different degrees of improvement.
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