Effect Of MAX And Their Derivatives On The Formation Of Fuel Cells Key Components

MAX and MXene have gradually become a research hotspot in the field of new materials.Since the surface of MXene contains a hydrophilic oxygen-containing functional group,it has strong electrical conductivity,stability,and mechanical properties.When combined with the electrolyte membrane matrix material,it can provide more paths for the transport of ions.Its nanometer size can also fill the fine pores between the substrates,which can improve the mechanical properties and electrochemical properties of the electrolyte membrane.The MAX phase material has high electrical conductivity,stability and mechanical strength.Its unique elemental composition also provides good corrosion resistance.When mixed with composite bipolar plate materials,it can increase the conductivity,bending strength and corrosion resistance of the plate.In this paper,Ti₃C₂T_x-MXene was used to dope the Sm_0.2Ce_0.8O_1.9 electrolyte matrix to study the electrochemical and mechanical properties of the composite membrane.The expanded graphite/polyimide matrix material was composited with Ti₃AlC₂-MAX to study the electrical conductivity,flexural strength and corrosion resistance of the composite bipolar plates.In addition,for the hot press forming process of composite bipolar plates,a composite bipolar plate forming die device with automatic demoulding is designed.In this paper,SDC powder which is prepared by glycine combustion method mixed with Ti₃C₂T_x-MXene and pressed into a composite membrane.The mechanical properties of the composite membrane is much better.The fracture toughness of the composite membrane is more than four times of the pure SDC membrane.The conductivity of 5wt.%Ti₃C₂T_x/SDC composite membrane has a significant improvement between 450℃ and 600℃.At 600℃,the conductivity of the composite membrane is 9 times of the pure SDC membrane.The cell performance of the 5wt.%Ti₃C₂T_x/SDC composite membrane is better than that of the pure SDC membrane,and the open circuit voltage is increased by 0.08V.The maximum power density is 2.5times of the pure SDC membrane.In this paper,Ti₃AlC₂-MAX was doped into the expanded graphite/polyimide（EG/PI）composite matrix by mechanical mixing method.The Ti₃AlC₂/EG/PI composite is prepared by hot press forming.It is found that with the increase of the PI content,the density and conductivity of bipolar plates are gradually reduced.The corrosion resistance is gradually enhanced,and the flexural strength and hardness are first to rise and then fall.After doping Ti₃AlC₂-MAX particles,the density,conductivity,flexural strength,hardness and corrosion resistance of the composite bipolar plates are improved.In this paper,an automatic demoulding mechanism is designed and applied to the composite bipolar plate forming mold.The frame hydraulic machine with heating is selected,and the expanded graphite/polyimide is selected as the material matrix.The feasibility of the automatic demoulding mechanism is tested.The result shows the designed composite bipolar plate forming mold is basically reasonable.The hot press forming of the composite bipolar plate can be completed in the mold.The plate can be separated and released without any loss.This proves the feasibility of the automatic demoulding mechanism.