Fossil fuel is the main energy resources of the world. About 80-90% of its primary energy need to supply by oil, coal, natural gas, and oil shale [1]. These energy resources will also be of importance in the future but non-renewable and cause problems to the environment as a result of their relatively high amount of carbon dioxide (CO2), carbon monoxide (CO), and other environmentally harmful emissions. We are investigating to look for alternative energy resources which are clean, safe, and long-term reliable. Thermoelectricity is one of the renewable energy resources that has been widely investigated and is expected to be feasible in the near future. Moreover, it is a clean energy generation, since it can directly convert heat to electrical energy by using non-polluting thermoelectric devices. These are reasons for the growing interest in further research and development of the thermoelectric technology. The search for new thermoelectric materials is important that the transition metal oxides were interested such as p-type Ca3Co4O9 [2-7] and n-type CaMnO3 [8-12]. There have been synthesized using different techniques in the form of powder and bulk. However, the doped metals have been expected to be one of the candidates for good thermoelectric materials, including thermoelectric module consists of two or more materials of p-type and n-type [13-15]. Recently, the thermoelectric module is also being used as the thermoelectric generators, thermoelectric coolers, etc. [16-17].
Recent advances on biomass-fueled microbial fuel cell