Advancements in Enhancement Strategies for Piezoelectric Nanogenerator Output Performance and Their Applications in Self-Powered Sensors

Given the increasing prevalence of the Internet of Things (IoT) in various aspects of modern society, issues concerning environmental problems and the limited lifespan of batteries are becoming more acute. As a renewable energy technology with multiple advantages such as environmental friendliness, compact size, and long lifespan, piezoelectric nanogenerators (PENGs) have broad application prospects in wearable devices and self-powered sensors. However, compared to triboelectric nanogenerators (TENGs) and pyroelectric nanogenerators (PyNGs), the output performance of PENG is not ideal, which limits its practical application in sensors. Therefore, it is crucial to develop efficient conversion and high-output PENG. This article starts from this point and summarizes three major strategies to enhance the piezoelectric output of PENG, including chemical doping, fiber orientation, and surface modification. It also elaborates on the mechanisms by which different strategies improve the performance of PENG from the perspectives of dipole orientation and interface interactions. Additionally, the working principles, material selection, and fabrication methods of PENG are discussed in detail, with particular emphasis on the unique advantages of the electrospinning process in enhancing the output performance of PENG. Second, the applications of high-output PENG in human motion detection, physiological medical monitoring, and industrial monitoring are reviewed. Finally, insights and prospects for future research directions and development were proposed, elaborating on the challenges and possible solutions of integrating PENG into large-scale sensor networks or IoT systems in the future from the aspects of energy output, environmental adaptability and reliability, large-scale integration and communication support, as well as cost and manufacturing processes.