Preparation And Study Of Composite Materials Based On Two-Dimensional Nanomaterial Mxene

MXene,a two-dimensional nanomaterial,becomes a major research hotspot in the field of nanomaterials due to its unique physical and chemical properties.Mxene contains the hydrophilic functional groups on its surface and exhibits high mechanical strength and molding characteristics.MXene mixed with substrate matrix materials to fabricate the composite membrane for fuel cells could provide more sites for ionic transmittance because of the hydrophilic functional groups on the surface.The capability of remaing the water and acid is also elevated to improve the proton conductivity and the mechanical properties.In this paper,a two-dimensional inorganic nanomaterials Ti₃C₂T_x-MXenes is mixed with polybenzimidazole（PBI）and ceramic solid acid（SnP₂O₇/BPO₄）to form the composite materials and also the physical and chemical properties are investigated.Ti₃C₂T_x-MXene has high temperature resistance and excellent mechanical properties that is expected to enhance the fracture toughness of ceramic,so it is mixed with Al₂O₃ and the mechanical properties are investigated.In this paper,Ti₃C₂T_x-MXene was synthesized and incorporated into the polybenzimidazole（PBI）matrix by solution tape casting.The proton conductivity of 3wt.%Ti₃C₂T_x/PBI is more than twice of the pristine PBI membrane in the temperature range of 100¹70℃.At 150℃the peak power density based on composite membrane increased by 30%comparing to the prisitine PBI membrane.3 wt.%Ti₃C₂T_x addition in the electrolyte improve the mechanical properties and thermal stability as well.The elongation at break of the phosphoric acid-doped 3 wt.%Ti₃C₂T_x/PBI composite is 1.5times of the pristine PBI membrane at 150℃.The strength and Young’s modulus are 1.5and 1.7 times,respectively.This study indicates that MXene has potential applications in solid proton acid electrolyte membranes fuel cells.In this paper,the influence of MXene on the mechanical properties of ceramic materials is explored.Ti₃C₂T_x-MXene is added into a inorganic solid acid composite matrix（SnP₂O₇/BPO₄）by physical mixing.The cross section morphology of powders and sintered body are characterized by XRD and SEM.The conductivity of the electrolyte is tested by AC impedance method.The results show that the 3 wt.%Ti₃C₂T_x/SnP₂O₇/BPO₄ composite electrolyte is more compact than the pure SnP₂O₇/BPO₄ membrane.The proton conductivity of 3 wt.%Ti₃C₂T_x/SnP₂O₇/BPO₄ is between 6.49×10^-3 S·cm^-1?8.43×10^-3 S·cm^-1 in the range of 150?250oC,which is three times of pure SnP₂O₇,and is 1.5 times of SnP₂O₇/BPO₄ composite membrane.Ti₃C₂T_x was added into alumina（Al₂O₃）powders by physical mixing with different concentrations and sintering temperatures.The properties influences of Ti₃C₂T_x-MXene into composite ceramic materials are investigated by structure observation and mechanical property test.The results show that MXene is well dispersed in the ceramic matrix and the mechanical properties of alumina sintered body are significantly enhanced.The fracture toughness,flexural strength and hardness of Ti₃C₂T_x/Al₂O₃increased by about 3 times,1.5 times and 3 times comparing to pristine Al₂O₃respectively.Finally,the toughening mechanism of Ti₃C₂T_x in the alumina matrix was discussed.