Dear XFNANO customers:

Advanced Materials (IF 19.791), published in July 2018, reported the important research progress of professor zhang yue of Beijing university of science and technology in the study of self-cleaning and self-charging power system with the title An Amphiphobic Hydraulic Triboelectric Nanogenerator for a Self-Cleaning and Self-Charging Power System.

In this work, the research group fabricated a wearable, self-cleaning/charging power system (SPS) which was charged by water energy to satisfy the energy demands. The SPS consists of a H-TENG with amphiphobic surface and several FSCs. The α-Fe2O3/RGO composite was synthesized as the active material of the FSCs to achieve a high performance. Finally, the SPS was designed to be a power raincoat, which successfully harvested the water energy and continually powered a light-emitting diode (LED) to realize the whole self-powered system. This work presents a solution to satisfy the increasing demands of utilizing sustainable and stable power in wearable electronics.

The structure and self-cleaning property of the SPS

The structure of SPS is depicted in Figure 1a. The SPS contains two primary components of a H-TENG which has a coated surface on the polytetrafluoroethylene (PTFE) and four embedded FSCs. The back side of the SPS was encapsulated completely by polydimethylsiloxane (PDMS) to prevent water permeation. The SPS converts the energy from water drops to electrical energy and stores it in the FSCs. The photo of the droplets of some typical liquids on the coated surface of the H-TENG is shown in Figure 1b. Water, mineral oil, gasoline droplets exhibit a spherical shape on the surface and can easily roll off. The scanning electron microscope (SEM) image of the microstructure of the coated surface of the H-TENG is shown in Figure 1c. The coated surface of the H-TENG consists of many nanometer-scale particles and pores, which are generated with the spray method. As shown in Figure 1d, the contact angles (CAs) of water, mineral oil, and gasoline are 115.53°, 114.64°, and 109.05°, respectively. To demonstrate the self-cleaning effect of the H-TENG, the H-TENG (1 cm × 1 cm) and a PTFE with the same size were dusted by active carbon. For cleaning of surfaces, the H-TENG and the PTFE were fixed with a titled angle of 45° and 5 mL water released from a syringe to the surfaces. In the initial state, photographs indicate that both H-TENG and PTFE are white (Figure 1e,f). After the active carbon sprayed randomly on the surfaces, the surfaces are all polluted to be black. The active carbon on the coated surface of H-TENG was removed after the cleaning process, while the surface of PTFE was still black. Therefore, the cleaning effect can be achieved by actual raindrop or water of taps, which is important for practical application of H-TENG.

SPS is used in powder raincoats

As a demonstration of scavenging water energy such as raindrops to provide power for portable and wearable electronics, Figure 5e shows a red LED on chest of the SPS-based power raincoat. When the region of power raincoat which contains H-TENG was showered, the water energy was harvested by the H-TENG and then converted to electric energy. After showering the power raincoat by water for 100 s, the LED could be lit by the power raincoat (Figure 5e,f). The time of the discharging process can sustain for more than 300 s.

The raw material graphene oxide used to prepare α-Fe2O3 / RGO as FSCs active material is from XFNANO.It is a great honor for XFNANO to provide high quality graphene oxide materials for researchers.