The triboelectric nanogenerator is assembled from two materials with different polarities. The positive electrode material is usually metal (such as silver, copper, aluminum) or metal oxide (such as zinc oxide, indium tin oxide). However, metals are easily oxidized and corroded in the environment, and metal oxides have poor flexibility, which affects the stability and application fields of TENG. Therefore, polymer cathode materials with excellent stability and plasticity began to attract attention, such as polyamide, cellulose, and polypyrrole. However, compared with metal cathode materials, the electrical signal output of TENG with polymer as cathode material is much lower. Therefore, there is an urgent need to improve the electrical signal output of all-polymer-based TENG.
Recently, Professor Shaoqin Sarah Gong (corresponding author), Dr. Qifeng Zheng and visiting professor Liming Fang of South China University of Technology (co-first author) from the University of Wisconsin-Madison reported on a flexible triboelectric nanopower generation based on polymer aerogel Machine (A-NG). The positive electrode material is cellulose (CNF) or chitosan (CTS) aerogel membrane, and the negative electrode material is porous polydimethylsiloxane (PDMS) or polyimide (PI) aerogel. Compared with the corresponding solid structure electrode, the aerogel electrode significantly increases the output power of the triboelectric nanogenerator by 11 times.
Schematic diagram of a friction nanogenerator (A-NG) based on polymer aerogel
The paper also compared the influence of the material type, porosity, and specific surface area of polymer aerogel electrodes on the electrical properties of TENG. It was found that the output of A-NG was increased with the difference in polarity and porosity of the positive and negative electrode materials. The voltage increases sharply. The A-NG assembled by chitosan with a porosity of 86% and PI with a porosity of 92% can output a voltage of 60.6V and a current of 7.7μA under a pressure of ~0.03 MPa, and its area power density It reaches 2.33W/m2, which is enough to drive LED and other devices or charge capacitors.
The influence of PI aerogels with different porosity on the voltage output of P-CTS/P-PI A-NGs
In this work, for the first time, the porous polymer material was used as the positive and negative electrodes of the friction nanogenerator at the same time, and the influence mechanism of the material pores on the TENG electrical signal output was analyzed. In the process of contact and separation of the positive and negative electrodes, in addition to the positive and negative electrostatic charges generated on the contact surface, the hole surface will also generate additional charges due to the electrostatic induction effect. The extra charges accumulated on the surface of the hole will cause a greater induced potential difference between the positive and negative electrodes, thus Significantly improve the electrical signal output. In addition, this work used the chemical vapor deposition method to modify the pore surface of the cellulose aerogel with aminosilanization to improve its positive electrical polarity, so that the electrical signal output of TENG was increased by 3 times compared with that before the modification.
Schematic diagram of A-NG friction generator based on porous polymer aerogel
This research uses environmentally-friendly natural polymers to replace expensive and corrosive metals as cathode materials, and adjusts the electrical output performance of triboelectric nanogenerators through simple methods such as changing aerogel porosity and surface chemical modification. , The development of high-performance flexible energy capture devices has reference value.
(Source: Frontiers of Polymer Science, reprinted from China Powder Network)
