The advancement of digital microfluidics technology has been pivotal in academic research and engineering applications. However, the prevailing limitation is that traditional voltage sources generate an excess of joule heat, adversely impacting droplet operation. Moreover, the power supply equipment required by digital microfluidics limits its applications. Here, we propose a self-powered microdroplet manipulation (SMDM) via triboelectric nanogenerator (TENG), which presents a capability for splitting and mixing different kinds of droplets. Fundamentally, SMDM is based on the electroosmotic flow principle, thereby enabling droplet splitting in the range of from 2 μL to 630 μL. Notably, for droplet splitting in the range of from 5 μL to 60 μL, the TENG only requires a power output ranging from 2.704 mW to 6.084 mW. In addition, SMDM demonstrates proficiency in droplet mixing, which achieves complete mixing of 10 μL droplets in 60 s, and 30 μL droplets in a mere 53 s. Therefore, leveraging the strengths of the TENG, a self-powered microdroplet manipulated system is designed for digital microfluidics. It carries significant advantages over the traditional voltage source, including self-powered, low-joule heat, increased safety, and enhanced portability. This research provides a new solution for portable applications of digital microfluidics.

The monitoring of vehicle motion states is a key factor to ensure smooth, safe and efficient management of traffic in intelligent transportation systems. However, employing multiple sensors for vehicle motion states monitoring not only increases system costs but also complicates the wiring. Here, we propose an integrated magnetic-assisted self-powered vehicle motion sensor (MSVMS) based on a triboelectric nanogenerator for real-time monitoring of vehicle motion states, including acceleration, angular speed, and inclination angle. By introducing a magnetic repulsion adjustment system, the sensor can achieve automatic resetting and effectively monitor the vehicle's motion state during normal driving. Experimental results indicate that the EMG unit can achieve a maximum peak power of 4.5 mW at an optimal load resistance of 1 MΩ. Meanwhile, the TENG unit demonstrated good sensing performance for acceleration, angular speed, and inclination angle, with fitting coefficients of 0.99, 0.979, and 0.978, respectively. Finally, the feasibility of the MSVMS in monitoring acceleration magnitude and direction is verified in a vehicle motion sensing system and actual vehicle test scenarios. This work further validates the potential application prospects of MSVMS in intelligent transportation systems.

Ocean wave energy is a significant and promising source of renewable energy. However, the energy harvesting is challenging due to the multi-directional nature of waves. This paper proposes a magnetic-field-assisted triboelectric nanogenerator (MFA-TENG) for harvesting multi-directional wave energy. By incorporating a magnetic field, the planar motion of the pendulum is converted into spatial motion, increasing the triggering of multilayered TENG (M-TENG) and enhancing the output energy of the MFA-TENG. Experimental results demonstrate that the output energy of the MFA-TENG is increased by 73% by utilizing the magnetic field. Moreover, a spring model based on the origami-structured M-TENG is established to analyze the effect of different equivalent stiffnesses on the performance of the M-TENG, aiming to obtain optimal output performance. The results showcase the impressive output performance of the M-TENG, generating outputs of 250 V, 18 μA, and 255 nC. Furthermore, the proposed MFA-TENG effectively harvests multi-directional wave energy under water-wave driven conditions. This study significantly enhances the ability of the MFA-TENG to harvest multi-directional wave energy and presents a promising approach for self-powered marine monitoring in the future.

The development and utilization of marine blue energy has become the focus of current research. A drawstring triboelectric nanogenerator with modular electrodes (DS-TENG) is proposed to harvest wave energy. Motion displacement and water wave adaptability are improved by using the drawstring structure in the DS-TENG. Furthermore, the modular electrode design is applied to improve the durability and replaceability of the generation units. The rationality of the structure is verified by theoretical analysis, and performance experiments on the fundamental output, displacement and frequency, durability and application are carried out. The DS-TENG can achieve output performance of 98.03 nC, 3.63 μA, 238.50 V and 923.92 µW at 150 mm and 1.0 Hz. In addition, the performance drops by 6.11% after 110,000 cycles for DS-TENG durability. This paper will provide reference for the design of TENG that adapts to a wide range of wave heights.

The development of automation industry is inseparable from the progress of sensing technology. As a promising self-powered sensing technology, the durability and stability of triboelectric sensor (TES) have always been inevitable challenges. Herein, a continuous charge supplement (CCS) strategy and an adaptive signal processing (ASP) method are proposed to improve the lifetime and robustness of TES. The CCS uses low friction brushes to increase the surface charge density of the dielectric, ensuring the reliability of sensing. A triboelectric mechanical motion sensor (TMMS) with CCS is designed, and its electrical signal is hardly attenuated after 1.5 million cycles after reasonable parameter optimization, which is unprecedented in linear TESs. After that, the dynamic characteristics of the CCS-TMMS are analyzed with error rates of less than 1% and 2% for displacement and velocity, respectively, and a signal-to-noise ratio of more than 35 dB. Also, the ASP used a signal conditioning circuit for impedance matching and analog-to-digital conversion to achieve a stable output of digital signals, while the integrated design and manufacture of each hardware module is achieved. Finally, an intelligent logistics transmission system (ILTS) capable of wirelessly monitoring multiple motion parameters is developed. This work is expected to contribute to automation industries such as smart factories and unmanned warehousing.

The wind energy in cities cannot be exploited effectively because natural wind is unstable and complex. Therefore, a triboelectric-electromagnetic hybrid generator with swing-blade structures (SBS-TEHG) was designed to effectively harvest intermittent and continuous wind energy in an urban environment. First, the spring structure and base were considered to realize the maximum output performance of triboelectric nanogenerators. Then, the computational fluid dynamics method was applied to optimize the structure of the SBS-TEHG to improve its aerodynamic performance. The starting wind speed of the SBS-TEHG was 2 m/s, and its energy conversion efficiency was 9.04%, 159% higher than that of the SBS-TEHG without guide plates at 4 m/s. The results demonstrated that the SBS-TEHG lit 105 light-emitting diodes (LEDs) under the intermittent-wind harvesting mode at a wind frequency of 1 Hz when the single swing blade operated, while a wireless PM_2.5 & PM₁₀ sensor was powered by the SBS-TEHG after a period of operation under the continuous-wind harvesting mode. The findings of this study provide a novel solution for low-speed wind energy harvesting in cities and demonstrate the potential of SBS-TEHG as a distributed energy source.

The environmental micro-energy harvested by the triboelectric–electromagnetic hybrid generator (TEHG) can power sensors and Internet of Things (IoT) nodes in smart agriculture. However, the separation structure of traditional TEHG raises the complexity of form and material, which is harmful to the miniaturization of the device. Herein, a single-material-substrated triboelectric–electromagnetic hybrid generator (SMS-TEHG) based on the flexible magnets is designed to achieve the structural integration of triboelectric nanogenerator (TENG) and electromagnetic generator (EMG). The flexible magnets serve as the electropositive triboelectric materials for TENG and the magnetic materials for EMG, simplifying the structural complexity of TEHG. The open-circuit voltage (V_OC) of the TENG and EMG are 187.2 and 9.0 V at 300 rpm, respectively. After 30,000 cycles of stability testing, the V_OC of the TENG and EMG retain about 95.6% and 99.3%, respectively. Additionally, the self-powered applications driven by SMS-TEHG in intelligent greenhouse have been successfully demonstrated, such as crop light supplementation, rain monitoring, and wireless temperature and humidity sensing. This work provides a new design for TEHG and possibilities for applying TEHG and IoT in smart agriculture.

To adapt to the low-velocity water flow closely related to human life, the natural energy can be efficiently harvested and used to power monitoring devices. Herein, a triboelectric soft fishtail (TE-SFT) driven by flow-induced vibration (FIV) effect is proposed based on the soft material synthesis technology. Specifically, inspired by the fishtail fin, a bluff body with the cross-section of fishtail-shaped is designed, and has a preferable vortex effect by fluid simulation. In power generation part, the triboelectric nanogenerator (TENG) is designed to act as an inertial pendulum structure by geometric method. Under the FIV effect, the TE-SFT driven by fishtail-shaped bluff body swings like a fish in the water and then brings the inertial pendulum to acquire the oscillation for harvesting energy from low-velocity water flow. The TE-SFT attains an open-circuit voltage (V_OC) of 200 V to 313 V at the flow velocities of 0.24 to 0.89 m/s. Additionally, after 30 days of water immersion, the V_OC of TE-SFT retains 96.81%. In demonstration, the TE-SFT is applied to power the temperature and humidity sensor through harvesting water flow energy. This work also provides a way for self-powered system based on the TENG and soft bionic fish in water environment.

The hydrokinetic energy of river current, as one of the essential and widespread renewable energies, is difficult to be harvested in low flow velocity and shallow water areas. In this work, a three-dimensional (3D) fully-enclosed triboelectric nanogenerator (FE-TENG) with bionic fish-like structure for harvesting hydrokinetic energy is reported, which is comprised of the triboelectric power-generation unit, bionic fish-like structure and connection unit. Through the bionic structure, the FE-TENG realizes zero head power generation in shallow water with low flow velocity. What’s more, the effect of external excitations and bionic structures on the electrical performance are systematically studied in this work. The FE-TENG can generate peak power density of 7 and 0.36 W/m³ respectively under the simulated swing state with frequency of 1.25 Hz and simulated river current with flow velocity of 0.81 m/s. In practical applications, due to the 3D fully-enclosed design, the FE-TENG immersed in water for 35 days demonstrates excellent immersion durability with undiminished electrical performance. Therefore, the work proposes an efficient method realizing zero head power generation, and provides a good candidate for long-term service in the river current.

The high-voltage power source is one of the important research directions of triboelectric nanogenerator (TENG). In this paper, a high-voltage output TENG (HVO-TENG) is proposed with direct current/alternating current (DC/AC) optimal combination method for wind energy harvesting. Through the optimal design of a direct current generation unit (DCGU) and an alternating current generation unit (ACGU), the HVO-TENG can produce DC voltage of 21.5 kV and AC voltage of 200 V, simultaneously. The HVO-TENG can continuously illuminate more than 6,000 light emitting diodes (LEDs), which is enough to drive more possible applications of TENG. Besides, this paper explored application experiments on HVO-TENG. Demonstrative experiments indicate that the high-voltage DC output is used for producing ozone, while the AC output can light up ultraviolet (UV) LEDs. The HVO-TENG can increase the ozone concentration (C) in an airtight container to 3 parts per million (ppm) after 7 h and continuously light up UV LEDs. All these demonstrations verify that the HVO-TENG has important guiding significance for designing high performance TENG.