| Moisture power generation is an emerging foreword research field developed in recent years.The current wet gas power generation mainly uses carbon nanomaterials,which is difficult to produce in large quantities and high in cost.The complicated devices and pore structures also affect its large-scale application.Biopolymer materials generally have the advantages of large reserves,degradable,renewable,good biocompatibility,etc.,and rich polar groups are distributed on the biomass polymer chain,which has good air absorption effect and excellent ion transmission.So the biopolymer materials is expected to be used for simulating biological processes and for generating electricity with moisture.Therefore,this study used cellulose nanofibers and silk nanofibers as the main research objects for experimental research.Firstly,the performance of two nanofibers as bio-nano generators in electricity harvest by moisture was studied.Herein,fully biological asymmetric ionic aerogels were fabricated from biological oppositely-charged nanofibrils through a facile freeze-casting method.When exposing to moisture,these nanofibrils may be hydrated by capturing moisture and thus simulate the charged nanochannels for ion transport.It has very good hygroscopicity(>1g·g-1).A layer of water film can be formed on the fiber surface.The two types of fiber surface groups dissociate and have different charges.The dissociated free ion charge properties are also opposite.They diffuse and neutralize along the water layer on the surface of the fiber,and a voltage?current?is generated between the two layers of fiber;the surface of the fiber can be restored to its original state by removing moisture.Ion dissociation and diffusion ions would induce directional movement of charges,resulting in induced potential.As the ambient humidity increases,the voltage also rises,resulting in voltages up to?115mV?cellulose nanofibers aerogel?and?120 mV?silk nanofibers aerogel?under saturated humidity and through structural optimization?Cellulose nanofiber aerogel thickness=6 mm,thickness ratio=1,porosity=99.3%;silk nanofibers aerogel thickness=5 mm,thickness ratio=1,porosity=99.6%?.With sustainability,biocompatibility and biodegradability,these biological nanogenerators may promise a low-cost and high-efficiency electricity harvest strategy from moist air,being capable of serving as self-powered wearable,biomedical and miniaturized electronic devices.Secondly,this study focuses on the mechanical and electrochemical properties of a Quaternization-silk nanofiber?Quatern-SNFs?membrane with a positive surface charge.Through chemical stripping,modification and mechanical homogenization,the silk nanofibers have positively charged groups-quaternary ammonium groups.This nanofiber membrane has superior mechanical properties?stress at break?42 MPa,strain?3.1%,Young's modulus?2.2 GPa?,and the composite membrane obtained by vacuum filtration with silk nanofibers with opposite charges can further improve its mechanical properties?stress at break?65 MPa,strain?3.2%,Young's modulus?2.85 GPa?.In addition,it has good electrochemical performance with nano-cellulose with opposite charge.The ion rectification ratio reaches?5.3,and the salt difference power generation voltage is maintained at?43 mV. |
PDF Full Text Request