Self-charging System Based On Triboelectric Nanogenerator-all-solid-state Lithium-ion Battery

Portable mobile power has received extensive attention as an energy storage device,but limited capacity and the need for periodic charging are important factors restricting its development.Triboelectric nanogenerators（TENGs）can harvest the dispersed,irregular,and ubiquitous mechanical energy in the environment and convert it into electrical energy.Therefore,developing self-charging systems based on TENGs and Li-ion batteries can effectively solve the problem of requiring periodic charging.However,the output performance of TENG has the characteristics of high voltage and low current.Therefore,improving the output current of TENG and developing an energy storage device suitable for it is an urgent problem to be solved for the application of self-charging systems.At the same time,the preparation of a management circuit that matches the output performance of the TENG is also the key to the construction of the self-charging system.It has now been proven that many methods can be used to improve the output performance of TENG,such as improving the dielectric properties of the friction layer by adding dielectric materials,constructing micro-nano structures or modification on the surface of the friction layer,optimizing the device structure,etc.Compared with traditional lithium-ion batteries,all-solid-state lithium-ion batteries have the advantages of better safety performance,higher energy density,and more stable cycles,so they are more suitable as energy storage devices for self-charging systems.Among them,solid electrolyte,as the core of all-solid-state lithium-ion battery,directly affects the overall performance of the device.In this thesis,0.94(Bi_0.5Na_0.5)Ti O₃-0.06Ba(Zr_0.25Ti_0.75)O₃（BNT-BZT）synthesized by solid-phase method,and the polyvinyl chloride（PVC）film with surface micro-nano structure was constructed by sandpaper.And the effect of different device structures on the output performance of TENG.Garnet-type Li₇La₃Zr₂O₁₂（LLZO）and NASICON-type Li_1.3Al_0.3Ti_1.7（PO₄）₃（LATP）were synthesized by sol-gel method and esterification,respectively.Two inorganic-polymer composite solid electrolytes,LLZO/PVDF-HFP and LATP/PVDF-HFP,were prepared with polyvinylidene fluoride-hexafluoropropylene（PVDF-HFP）,and their electrochemical properties were characterized.Using Two kinds of modified TENGs were constructed with all-solid-state lithium-ion batteries based on two composite solid-state electrolytes to build self-charging systems and their performances were tested.This paper mainly carries out the following work:（1）Adding BNT-BZT nanoparticles to polyvinylidene fluoride（PVDF）can effectively improve the output performance of TENG.When the doping amounts of BNT-BZT nanoparticles in BNT-BZT/PVDF is 9 wt%,the wind speed is 20.6 m/s,the device output performance can reach 405 V and 46μA,which is 120 V and 12μA higher than that of the TENG constructed with pure PVDF membrane.All-solid-state Li-ion batteries fabricated with Li Ni Mn Co O₂,Ni Co₂S₄,and LLZO as cathode,anode,and electrolyte,respectively,maintained a coulombic efficiency of 98.5%after 200cycles.The constructed TENG-all-solid-state lithium-ion battery self-charging system has good performance for collecting and converting wind energy and storing it.It can charge an all-solid-state lithium-ion battery from 0.5 V to 3.8 V in 60 minutes,and power LED lights and p H meters.（2）A turntable TENG for collecting rotational mechanical energy was constructed by using nylon membrane（PA）and copper foil as the friction material,respectively.The research shows that the output performance of the TENG is greatly affected by the rotor speed.With the increase of the speed,the output voltage of the TENG basically remains unchanged,but the output current increases linearly.When the rotor speed is500 rpm,the output current can reach 400μA,which is 10 times the output current when the rotor speed is 50 rpm.All-solid-state Li-ion batteries fabricated with Li Ni Mn Co O₂,Ni Co₂O₄,and LATP as cathode,anode,and electrolyte,respectively,maintained a coulombic efficiency above 95%after 200 cycles.The constructed TENG-all-solid-state lithium-ion battery self-charging system has good performance for converting rotational mechanical energy and storing it.The voltage of the all-solid-state lithium-ion battery can be charged from 0.5 V to 3 V within 5 minutes,and the temperature and humidity meters can be powered.（3）Zr C-Zr O₂ powder was used to modify the PVC membrane with micro-nano structure on the surface,and Zr C-Zr O₂/PVC composite membrane with surface microporous structure was prepared,and then a TENG for collecting wind energy was constructed.The results show that:When 1000-grit sandpaper is used to build micro-nano structures on the surface of PVC film,and the wind speed is 17.9 m/s,the output performance of the device is 306 V,34μA,which is 120 V and 10μA higher than the output voltage of the pure PVC film with smooth surface prepared by using glass plates,respectively.Adding 0.9%Zr C-Zr O₂ powder to the PVC film with surface micro-nano structure,when the wind speed is 17.9 m/s,the device output performance is 367 V and close to 39μA,which is about 60 V and 5μA higher than that of the pure PVC film.The TENG fabricated using the Zr C-Zr O₂/PVC composite film with surface micro-nano structure can drive 27 LED lights to work normally.