Direct Carbon Fuel Cell Based On Ce_0.8Sm_0.2O_1.9-(Li_0.67Na_0.33)₂CO₃ Composite Electrolyte

Direct carbon fuel cell?DCFC?dates back to more than 100 years.It is a device which can directly convert the chemical energy of solid carbon into electricity.Compared with the conventional coal-fired power generation,DCFC has many advantages,namely high efficiency,low pollution,low emission and low noise.A variety of carbon sources can be used as fuels for DCFC,such as activated carbon,carbon fiber,carbon black,coal and biomass.The theoretical efficiency of DCFC is 100% and the efficiency can reach 80% in reality.In recent years,DCFC has attracted more and more attention and has been investigated more and more intensively.This thesis introduces the development history,basic principle and advantage of DCFC.The research status of DCFC is also introduced.The preparation processes of fuel cell material and cell pellet as well as the constitution of DCFC test system are specified.The electrolyte material is composed of Ce_0.8Sm_0.2O_1.9?SDC?and Li₂CO₃-Na₂CO₃ eutectic carbonate.The cathode material is composed of lithiated NiO and electrolyte material.The fuel cell pellects with NiO anode layer have been fabricated by co-pressing and co-sintering and screen printing technology.Bituminous coal from Shanxi province and anthracite coal from Ningxia province are utilized as fuel for DCFC and the performance of fuel cell is investigated.At 750 ?,outputs of 190 and 164 mW cm-2 are achieved from the cells with bituminous coal and anthracite coal,respectively.Bituminous coal has a higher chemical oxidation activity as well as a higher electrochemical oxidation activity.SnO₂ is introduced into the anode of DCFC as anode material.Carbon fiber produced from pyrolysis of methane is used as fuel for DCFC with SnO₂ anode layer.The DCFC with NiO anode layer is also tested to be compared with the DCFC with SnO₂ anode layer.Maximum power densities of DCFCs with SnO₂ and NiO anode layers are 193 and 143 mW cm-2,respectively.The SnO₂ in the anode is reduced by carbon fiber or CO to form Sn,which can be electrochemical oxidated by O^2-.In this way,Sn/SnO₂ in the anode provides an additional approach for the conversion of carbon or CO.