Preparation And Application Of Flexible Nd₂Fe₁₄B/Organic Polymer Composite Triboelectric Materials

Triboelectric nanogenerator（TENG）can effectively collect scattered,low-quality,low-frequency mechanical energy in the environment,and the output electrical signal has the characteristics of high voltage and low current.In order to further improve the output characteristics of the generator,the electromagnetic generator（EMG）with low voltage and high current output characteristics is used to combine with it,which can learn from each other’s strengths and make up for the shortcomings,and the EMG can collect high-frequency energy in the environment,expanding the energy collection.Therefore,the triboelectric-electromagnetic hybrid nanogenerator（TEHG）is derived.In this paper,three flexible composite tribo-electromagnetic films were prepared by the blade coating method,which served as triboelectric materials and replaced the magnets in the traditional TEHG,reducing the mass of the generator and simplifying the structure.And three kinds of TEHG were designed based on the composite membrane,and the output performance was studied in detail and its application in different fields was carried out.（1）A contact separation mode TEHG based on flexible Nd₂Fe₁₄B/polyvinyl chloride(Nd₂Fe₁₄B/PVC)composite films is proposed to harvest mechanical energy in the environment.Here,Nd₂Fe₁₄B powder was embedded in PVC film to produce a composite film with both triboelectric and ferromagnetic properties to replace the relatively large magnets in traditional EMG.The TENG in the designed TEHG can generate an output electrical signal of up to 422 V and 60.5μA under the stable input condition of 3.8 N and2.1 Hz provided by the linear motor,and output a peak power of 4.5 m W under the condition of an external load resistance of 5 MΩ.Generate an output electrical signal of approximately 0.28 V,1.4 m A,delivering a peak output power of 0.11 m W with a load resistance of 200Ω.Compared with a single energy harvesting unit（TENG or EMG）,TEHG exhibits good stability and has better charging performance.A 470μF capacitor can be charged to 3 V in 360 s,and the stored energy can successfully power a digital thermohygrometer and a vernier caliper continuously.（2）A rotating TEHG based on a flexible Nd₂Fe₁₄B/ethylcellulose(Nd₂Fe₁₄B/EC)composite film,including a rotating EMG and an independent sliding mode TENG,is designed for harvesting wind energy in the environment.A composite film with both triboelectric and ferromagnetic properties is prepared to replace the magnet,which can greatly reduced the weight of the rotor.The performance of the composite generator is optimized by designing interdigitated electrodes with different electrode gaps.The TENG unit in the TEHG designed with an electrode gap between 2 mm can generate an output electrical signal of about 54.83 V and 5.41μA under the condition of 15.5 m/s,and output a peak power of 99.22μW under the condition of an external load resistance of 10 MΩ.The EMG can generate about the output electrical signal of 0.158 V,59.27μA can provide a peak output power of 2.53μW with a load resistance of 2300Ω.Compare with TENG or EMG alone,TEHG exhibits better charging performance.A 100μF capacitor can be charged to 11.6 V and a 470μF capacitor can be charged to 3.4 V in 600 s,and the stored energy can power the operation of the microelectronic device.（3）A TEHG based on a flexible Nd₂Fe₁₄B/polydimethylsiloxane(Nd₂Fe₁₄B/PDMS)composite film is proposed to harvest mechanical energy in the environment.The plastic dielectric material is replaced by a rubber-like dielectric material with high toughness,and the doping content of Nd₂Fe₁₄B particles of the dielectric material is increased,thereby improving the output performance of the EMG unit,while ensuring that the performance of the TENG unit will not decline.The friction surface was then treated with sandpaper to further to improve the output performance of TENG.The TENG in the designed TEHG can generate an output electrical signal of up to 392 V and 41.52μA under the stable input condition of 3.0 N and 2.1 Hz provided by the linear motor,and the EMG can generate an output electrical signal of about 0.33 V and 1.57 m A.The overall output performance of TEHG based on the magnetic-dielectric composite film will be improved and its application scope will be expanded.