Manufacturing And Performance Study Of Methanol Controlling Carbon Fibers In PAB-DMFC

The passive air breathing direct methanol fuel cell(PAB-DMFC)is a kind of efficient and clean power device,has been recognized as the fourth large scale power generation under thermal power,hydraulic power and nuclear power.However,there are some challenges such as methanol crossover and product management which limit the improvement of cell performance.In this situation,the article applies electrospinning and heat treatment process to prepare the polyacrylonitrile(PAN)based carbon nanofiber with nano-porous structure,which is acting as the cell methanol barrier medium.Besides,current collectors with different structure parameters are designed systematically to investigate its influencing mechanism on the performance of single PAB-DMFC.Based on the well-performance current collector,the effects of carbon nanofiber on cell methanol crossover,products management and cell performance are studied.The main contents include:1.Investigation of electrospinning process:The effects of electrospinning parameters on the diameter and morphology of PAN fiber are systematically studies.The comparative experiments show that PAN spinning solutions have the great impact on the diameter and morphology of PAN fiber.Specific electrostatic spinning parameters: the concentration of PAN spinning solutions are 11%,14% and 17% respectively,the spinning voltage is 15 kV,the spinning collecting distance is 14 cm,the liquid injection rate is 0.4m L/h.2.Manufacture of carbon nanofiber and characterization of key physical properties:Heat treatments including pre-oxidation and carbonization of PAN fiber are applied to prepare the carbon nanofiber.Considering the actual operating conditions of PAB-DMFC and focusing the functions of carbon nanofiber,the influencing parameters including surface micro-structure,electrical conductivity,infrared spectrum analysis and wettability of methanol are characterized.The effects of different concentrations of PAN spinning solutions and different carbonizing temperatures on the final carbon nanofiber are also investigated.3.Sturucture study of PAB-DMFC current collectors:Before the application of the carbon nanofiber,gold-coated printed circuit boards are made as the base material of PAB-DMFC current collectors.Several different shapes of current collectors are designs and manufactures while combined with its key structure parameters.The effects of different current collectors structure parameters including hole opening rate,hole shape,hole uniformity,slot slop,assembly position of cathode and anode current collectors and etc to the cell performance are studied.A suitable type of current collectors which yields the better performance is selected after comparision.4.Performance study of PAB-DMFC with carbon fiber:The effects of carbon fiber manufactured by different concentrations of PAN spinning solution and different carbonizing temperatures on the performance of PAB-DMFC are investigated based on the suitable current collectors.The results demonstrate that the performance of the novel PAB-DMFC applied the PAN based carbon fiber can be significantly improved when compared with the traditional PAB-DMFC,and a most remarkable improvement as high as 53.54% is achieved.Additionally,carbon nanofiber can effectively advance the dynamic response rate,ensuring a stably long operation time under high-power output of PAB-DMFC.