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Power management is an efficacious route to promote the development of triboelectric nanogenerators (TENGs), in which the buck switch for efficient energy extraction has always been a challenge. Here, we propose a three-port cantilever buck switch which can autonomously release energy from the TENG in maximum by the generated electrostatic field of the TENG. The influence of closing voltage of the buck switch on different structure parameters has been thoroughly investigated. The U-Q curve indicates that the optimal energy extraction can reach 90.86%, and the matched impedance of the TENG is reduced from 60 MΩ to 470 kΩ. Compared to the output power at matched impedance, the average power managed by this three-port cantilever buck switch is increased by 1.554 times, which can power the Bluetooth device, electronic watch, calculator and thermo-meter. This work has realized ultra-efficient power management of TENG by leveraging an autonomous cantilever buck switch, which can contribute to the efficient utilization of micromechanical energy. • A three-port cantilever buck switch controlled by the electrostatic field of the TENG for its power management is pioneered. • A detailed analysis of the force-electricity conversion process has been conducted. • U-Q curve and P-R curve has been linked to characterize the output efficiency for the first time. [ABSTRACT FROM AUTHOR]

[Display omitted] • A stretchable electret achieves high surface charge and long charge stability. • A stretchable electret-based TENG achieves high charge density (0.2 mC m−2). • A power management module enhances power storage efficiency of the TENG. • The self-charging system provides a stable power supply for wearable electronics. Stretchable power sources capable of accommodating large deformations are urgently demanded for various stretchable and wearable electronics. In this work, we report a stretchable electret-based triboelectric nanogenerator (SEB-TENG) consisting of elastomeric electret as electrification materials and organo-hydrogels as electrodes. The electret elastomer, prepared by uniformly dispersing SiO 2 nanoparticles in the elastomer matrix and thermally injecting static charges, obtains a high surface potential, high tensile strain (796%), and long stability. Then, the SEB-TENG device also achieves high stretchability (423%) and high charge density (0.2 mC m−2). Furthermore, a power management module (PMM) is designed to maximize the energy utilization of the SEB-TENG. The integrated self-charging system can be sufficiently used to constantly power a watch, or charge a Li-ion coin cell which subsequently provides sustainable power supplies to a digital thermometer. This work provides a viable approach to simultaneously achieve high output performances and high stretchability of integrated power sources. [ABSTRACT FROM AUTHOR]

[Display omitted] • H-SiO 2 and PF as fillers to improve the dielectric properties of PFS films. • The performance of TENGs delivered an enhancement by 13 times. • Multiple nanoscales is more favorable to achieve high performance of TENGs. Triboelectric nanogenerators (TENGs), capable of harvesting distributed energy from the environment, have provided a viable solution for self-powered wearable electronics. However, their low power density and susceptibility to contamination still severely limit their practical application. Herein, we reported a "two-step" strategy to implement a waterproof self-powered wearable electronic device based on TENG. Firstly, Perfluoropolyether (PF) and hollow hierarchical silica (H-SiO 2) as fillers significantly improve the dielectric properties of polydimethylsiloxane (PDMS) composite films (PFS films) through polarization effect. Then the nano bumps of 10–30 nm are created on the surface of the films by surface etching, the bumps can increase the contact area of TENG. The voltage of TENG is improved from ∼ 67 V to ∼ 910 V and the current is improved from ∼ 1 μA to ∼ 25 μA. What's more, the investigation of the surface structure of the PFS composite films by Atomic Force Microscope (AFM) revealed that the synergistic combination of multiple nanoscales (10–30 nm, 60–80 nm, 300–500 nm) is more favorable to achieve high performance of TENG. The surface structure composed of multiple nanoscales endows PFS with excellent superhydrophobicity. The PFS films remained fine performance after 40,000 drops of water and 90 days. This work achieves high performance and water resistance of TENG, demonstrating great potential in the field of self-powered wearable electronic devices. [ABSTRACT FROM AUTHOR]

A compact, springless, easy-to-process kirigami-inspired TENG (KI-TENG) is developed. The frequency responses of the KI-TENG under the influence of mass, acceleration, and initial distance are investigated in detail to optimize its structural design. Moreover, the TENG coupled with the kirigami structure could collect ultra-wide-band vibration energy and as a sensor measuring acceleration. [Display omitted] • A compact and springless kirigami-inspired TENG (KI-TENG) is developed. • The frequency response characteristics of the KI-TENG are investigated. • The KI-TENG can harvest ultra-wide-band vibration energy from 2 to 49 Hz. • The output of the KI-TENG at different vibration tilt angles is explored. • The KI-TENG can effectively monitor acceleration changes from 1 to 9 m/s2. Triboelectric Nanogenerators (TENGs) based on spring-assisted structures play a central role in scavenging vibrational energy that is widely available in the natural environment. However, they suffer from difficulties in adjusting the stiffness and bonding the springs to the triboelectric layer. Here, a kirigami-inspired TENG (KI-TENG) with a kirigami structure is demonstrated, which can be used as an ultra-wide-band vibrational energy harvester and self-powered acceleration sensor. The triboelectric layer of the KI-TENG can be easily processed into the kirigami structure with one or two-degree-of-freedom by laser cutting technology. The frequency responses of the KI-TENG under the influence of mass, acceleration, and initial distance are investigated in detail to optimize the structural design. With optimized structural parameters, the KI-TENG can not only harvest broadband vibration energy from 2 to 49 Hz in vertical vibration state but also obtain high output performance over a wide frequency range in horizontal vibration state. Moreover, the KI-TENG can be used as a sensor measuring acceleration from 1 to 9 m/s2. This work demonstrates a compact TENG coupled with the kirigami structure for energy harvesting and active sensing, which has great prospects in intelligent plants, artificial intelligence, and the internet age. [ABSTRACT FROM AUTHOR]

The use of renewable resources to generate energy is one of the most important policy goals in the energy sector. One method to use renewable resources is to apply integrated systems. In this study, an optimal multi-objective integrated system has been applied to power generation. The proposed system includes wind turbines, hydroelectric power plants, and photovoltaic systems. To achieve maximum power generation with minimum fluctuations, a Developed Owl search algorithm (DOSA) with three pareto front solutions has been used. Also, the efficiency of the integrated system in different climate conditions is evaluated. The results of the pareto front show that the developed owl search algorithm is the closest algorithm to the pareto front. Therefore, it is the most accurate to improve the overall multi-objective integrated system. Among pareto front solutions, the second solution provides acceptable results for increasing power generation and reduction of fluctuations. Also, the results of the evaluation of the efficient integrated system in different climate conditions show that in wet conditions when solar radiation and wind are reduced, hydropower causes current to continue in the system by generating electricity and compensating for wind and PV energy loss. • A wind-photovoltaic-hydropower hybrid system has been used. • The Developed Owl search algorithm is used to improve efficiency of the system. • Three climatic conditions are used to analyze the efficiency of the hybrid system. • The system can continue to generate power well in different climate. [ABSTRACT FROM AUTHOR]