High-performance triboelectric nanogenerator with enhanced energy density based on single-step fluorocarbon plasma treatment

• Presented a simple and universal technique to enhance the energy density of TENG by using a single-step fluorocarbon plasma treatment.
• The maximum instantaneous energy area density is enhanced by 278%.
• The enhancement mechanism of this plasma treatment is theoretically analyzed by density functional theory at molecular level for the first time.
• Established environmental humidity as a new key criterion for future studies of TENG performance for practical applications, and a novel self-powered humidity monitoring sensor is proposed.
• First demonstration of successfully driving a neutral prosthesis (i.e., microneedle electrode array) to stimulate the frog's sciatic nerve.

Recently triboelectric nanogenerator (TENG) devices that transform environmental mechanical energy to electric power have been demonstrated as a renewable, clean and usable power source. However, the TENG output power still should be enhanced to better meet practical needs, and the working ability for practical applications should be further investigated. Here, we demonstrate a novel high-performance TENG by using a single-step fluorocarbon plasma treatment, which can significantly strengthen the TENG output performance. After the optimization of plasma treatment, the maximum instantaneous energy area density of the TENG with micro/nano hierarchical structures is enhanced by 278% to 4.85 mW/cm2, with a peak output voltage of 265 V and current density of 18.3 μA/cm2. The reliability and stability of this single-step fluorocarbon plasma enhancement process were widely and deeply investigated by systematically comparative experiments. The density functional theory (DFT) is employed to analyze the chemical modification mechanism of this fluorocarbon plasma treatment, modeling for the first time the energy required for electron transfer for different friction materials at molecular level based on first-principle calculations. The ability of this TENG to work in the practical environmental, especially in the biomedical field, has been demonstrated by the investigation of the effect of the key environmental factor (i.e., humidity) on the TENG output performance, and a quantitative relation has been figured out. Based on this relation, humidity is established as a new consideration for future studies of TENG performance, and a novel self-powered humidity monitoring sensor is proposed. This high-output TENG is also successfully applied to drive an implantable microneedle electrode array to stimulate a frog's sciatic nerve. This represents the first application of a TENG for sustainably powering a biomedical microsystem implanted in real biological tissue, moving closer to practical biomedical applications of TENGs.

We present a simple and universal technique to enhance the energy density of TENG by using a single-step fluorocarbon plasma treatment, achieving an increase of 2.78 times. The reliability and stability of this fluorocarbon plasma enhancement process were deeply investigated by systematically comparative experiments. The enhancement mechanism of this plasma treatment is theoretically analyzed by density functional theory (i.e., first-principle calculation) at molecular level for the first time. The quantitative relation between TENG output and environmental humidity is experimentally obtained, establishing a new key criterion for future studies of TENG performance for practical applications, and a novel self-powered humidity monitoring sensor is proposed. Additionally, this novel TENG is demonstrated to successfully drive a neutral prosthesis (i.e., microneedle electrode array) to stimulate a frog's sciatic nerve.Figure optionsDownload as PowerPoint slide