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Owing to their unique advantages, single‐electrode triboelectric nanogenerators (SETENGs) have gained wide attention and have been applied in myriad areas, especially in the burgeoning flexible/wearable electronics. However, there is still a lack of a clear understanding of SETENGs. For example, previous simulation models generally put the reference electrode perpendicularly below the working part, but in practice, the reference electrode is designed in various scenarios and noticeable differences in outputs often occur when the reference electrode changes. With SETENGs developing towards wearability and portability, its reference electrode is often required to be constructed inside the device. Consequently, to achieve optimum performance, it is essential to understand the reference electrode's influence on the outputs. Here, the influence of the reference electrode on the performance of SETENGs is systematically investigated and the targeted optimization strategies are thoroughly revealed. First, theoretical simulations are conducted to investigate the reference electrode's effect on the performance of SETENGs with different structures and in various working modes. Secondly, the theoretical results are certified through corresponding experiments. Based on the results, the targeted optimization strategies for SETENGs are comprehensively demonstrated. This work provides fundamental guidance for the development of TENGs and the design and fabrication of new electronic devices. [ABSTRACT FROM AUTHOR]

Abstract Since each individual has distinct gait characteristics, monitoring human motion can enable identity recognition. Here, we report a self-powered band that can recognize human identity through gait pattern which is achieved by detecting muscle activity. The self-powered band is a soft and stretchable triboelectric nanogenerator (TENG) that is biocompatible and low-cost, which is looped around human body parts and generates electrical outputs in response to body motions involving muscle activities. The band can quantitatively detect walking step, speed and distance. Furthermore, the detected unique motion pattern of each individual allows the band to be used for identity recognition such as personal computer login and employee clock in through gait monitoring and analysis. This work opens new frontiers for the development of self-powered electronics and inspires new thoughts in human-machine interface. Graphical abstract fx1 Highlights • Self-powered identity recognition through gait pattern is achieved using a soft and stretchable TENG band. • Gait pattern is recognized through detecting muscle activities by the TENG band. • Several kinds of biomechanical motions can be accurately detected using the TENG band. [ABSTRACT FROM AUTHOR]

Abstract Working in the ambient environment, the behavior of triboelectric nanogenerator (TENG) is inevitably limited by the air breakdown phenomenon. In this paper, the load characteristics of TENG considering the air breakdown effect are systematically studied. The maximum retainable surface charge density varies with resistive loads, and a saturation state is seen during the capacitive charging process in the TENG due to the air breakdown effect. The optimization criterion to maximize the TENG output was also investigated with the consideration of air breakdown effect. Through theoretical analysis and experimental verification, this work provides a solid criterion to guide the TENG design and operational process. Graphical abstract fx1 Highlights • Load characteristics of TENG considering the air breakdown effect (ABE) are studied. • The optimization criterion to maximize the TENG output is analyzed considering ABE. • The influences of parameters on TENG's behavior considering ABE are investigated. [ABSTRACT FROM AUTHOR]

In the field of automobiles and many other industries, there is an urgent demand for the sensing of high- g acceleration. In this paper, a self-powered high- g acceleration sensor based on a triboelectric nanogenerator is proposed for the first time. It is micro-fabricated with a total volume of 14 × 14 × 8 mm 3 , and its sensing ability is confirmed via a Machete hammer experiment, with a measurement range of up to 1.8 × 10 4 g , a sensitivity of 1.8 mV/ g , and a Pearson correlation coefficient of 0.99959. In addition, the output signal of this novel acceleration sensor has few clutters, which is beneficial for recognition and subsequent signal processing. The effects of the aluminum-electrode thickness on the sensitivity and linearity of the sensor are investigated via modeling, theoretical analysis, and experiment, providing a reliable basis for the parameter optimization of the structural design. Experiment results indicate that this novel acceleration sensor covers a wide measurement range and meets the urgent needs of monitoring various high- g impacts for military equipment and automobiles. [ABSTRACT FROM AUTHOR]

A bioinspired soft and stretchable triboelectric nanogenerator (TENG) is developed as energy-harvesting skin to drive personal electronics by scavenging biomechanical energy. Drawn inspiration from biological cells, the TENG consists of patterned interconnected cellular structures, with physiological saline as the electrode and silicone rubber as the encapsulation and triboelectric layer. The TENG can withstand a strain of 600% and has a transmittance of as high as 62.5%. The TENG can keep its high performance under various strain. The TENG also has the desirable features of biocompatibility, simple fabrication, light weight and environmental protection. The maximum instantaneous power density (2.3 Hz) and direct current power density of the TENG are ~ 11.6 W/m 2 and ~ 2.65 mW/m 2 respectively. Mounted on the skin, the TENG integrating with a power management unit can sustainably drive an electronic watch sorely by harvesting energy from hand motion. A stretchable self-charging power unit with a TENG and a micro supercapacitor sharing the same solution is created, with the solution as both the electrode of the TENG and the electrolyte of the supercapacitor. This work opens up new insights for clean power sources of skin-mounted electronics and promotes the development of sustainable energy supply for wearable and portable electronics. [ABSTRACT FROM AUTHOR]