Preparation Of Flexible Inorganic Oxide Nanofiber Membrane And Research On Its Hydrovoltaic Performance

Water,in the form of evaporation and humidity,is used as the driving force of hydrovoltaic technology,converting the kinetic energy of liquid or gaseous water molecules into electricity,playing an important role in the construction of self-powered devices and has become a research hotspot in recent years.Due to the excellent thermal and chemical stability of inorganic oxide materials,it has become a promising material for hydrovoltaic generation.However,the electrical performance of inorganic oxide materials currently prepared is poor with voltage lower than 0.5V.Owing to unstable pore structure and lack of flexibility,which limits the large-scale application of devices made by this material.The inorganic oxide nanofibers prepared by electrospinning technology have stable nano-channels,which can improve the electrical performance of devices.In addition,the nanofiber membranes prepared by the technology have outstanding flexibility,which is beneficial to realize the application in the wearable field.In this thesis,the electrospinning technology is adopted to prepare flexible inorganic oxide nanofiber membranes.In order to improve the performance of hydrovoltaic generation,the selection of materials,power generation methods,and optimization of electrical performance are explored.The flexible silicon dioxide(Si O₂)and titanium dioxide/zirconium dioxide(TiO₂/Zr O₂)inorganic oxide nanofiber membranes are prepared by electrospinning,and the performance of hydrovoltaic generation driven by water evaporation and humid air flow respectively of the flexible Si O₂ and TiO₂/Zr O₂ inorganic oxide nanofiber membranes are tested.The output performance of the generator has been improved.Details as follows:(1)Using sol-gel electrospinning technology and calcination process to prepare flexible Si O₂ nanofibers for hydrovoltaic generation driven by water evaporation.By characterizing the morphology and surface potential of Si O₂ nanofibers,different fiber diameters,fiber film thicknesses water evaporation rate,solution and electrode type on the output voltage of the device were explored.The results show that the power generation performance of the device is mainly attributed to the synergistic effect of the electrokinetic effect caused by water evaporation and the ion concentration difference between the upper and lower electrodes,and the optimal output voltage is up to 0.48 V.In addition,we improve the output of voltage and current through the connecting devices in series and parallel to power commercial digital calculators.(2)The flexible TiO₂/Zr O₂ composite nanofiber-based hydrovoltaic generation device is prepared by sol-gel electrospinning technology and calcination process for moist air-driven hydrovoltaic generation,and the microscopic morphology and flexibility of the TiO₂/Zr O₂composite nanofiber are characterized,and the mechanism of flexible molding is explored.The TiO₂/Zr O₂ nanofiber membrane has a good photocatalytic ability,which can decompose macromolecular particles of organic matter,thereby realizing the self-cleaning performance of the device and improving its the service life.(3)In order to further optimize the output performance of the device,TiO₂/Zr O₂ composite nanofiber membranes are prepared by adjusting the composite molar ratio of Ti⁴⁺and Zr⁴⁺and calcination process parameters,and the output voltage performance of these fiber membranes under different parameters are studied.The results show that when the molar ratio of Ti⁴⁺to Zr⁴⁺is 3:1 and the calcination temperature is 600?,the output voltage of the device increases from0.58 V to 0.8 V,reaching the highest voltage in inorganic oxide power generation devices.The output voltage of the device could be further improved through connecting the device in series and parallel.The flexibility of the fiber membrane remains excellent even being subjected to bending test of 1000 times,and the voltage change rate is below 15%,showing good performance stability.It realizes the integration of mechanical flexibility and high performance characteristics,and further expands the application fields of nano generator.