Mechanical modulations for enhancing energy harvesting: Principles, methods and applications

Mimicking Human and Biological Skins for Multifunctional Skin Electronics

Following the rapid development of lightweight and flexible smart electronic products, providing energy for these electronics has become a hot research topic. The human body produces considerable mechanical and thermal energy during daily activities, which could be used to power most wearable electronics. In this context, fiber-based energy conversion devices (FBECD) are proposed as candidates for effective conversion of human-body energy into electricity for powering wearable electronics. Herein, functional materials, fiber fabrication techniques, and device design strategies for different classes of FBECD based on piezoelectricity, triboelectricity, electrostaticity, and thermoelectricity are comprehensively reviewed. An overview of fiber-based self-powered systems and sensors according to their superior flexibility and cost-effectiveness is also presented. Finally, the challenges and opportunities in the field of fiber-based energy conversion are discussed.

Fiber-Based Energy Conversion Devices for Human-Body Energy Harvesting

With the rapid development of the Internet of Things (IoT), the number of sensors utilized for the IoT is expected to exceed 200 billion by 2025. Thus, sustainable energy supplies without the recharging and replacement of the charge storage device have become increasingly important. Among various energy harvesters, the triboelectric nanogenerator (TENG) has attracted considerable attention due to its high instantaneous output power, broad selection of available materials, eco-friendly and inexpensive fabrication process, and various working modes customized for target applications. The TENG harvests electrical energy from wasted mechanical energy in the ambient environment. Three types of operational modes based on contact-separation, sliding, and freestanding are reviewed for two different configurations with a double-electrode and a single-electrode structure in the TENGs. Various charge transfer mechanisms to explain the operational principles of TENGs during triboelectrification are also reviewed for electron, ion, and material transfers. Thereafter, diverse methodologies to enhance the output power considering the energy harvesting efficiency and energy transferring efficiency are surveyed. Moreover, approaches involving not only energy harvesting by a TENG but also energy storage by a charge storage device are also reviewed. Finally, a variety of applications with TENGs are introduced. This review can help to advance TENGs for use in self-powered sensors, energy harvesters, and other systems. It can also contribute to assisting with more comprehensive and rational designs of TENGs for various applications.

Triboelectric Nanogenerator: Structure, Mechanism, and Applications.

A linear-to-rotary hybrid nanogenerator for high-performance wearable biomechanical energy harvesting

Nanopillar-array architectured PDMS-based triboelectric nanogenerator integrated with a windmill model for effective wind energy harvesting

Exo-shoe triboelectric nanogenerator: Toward high-performance wearable biomechanical energy harvester

Universal biomechanical energy harvesting from joint movements using a direction-switchable triboelectric nanogenerator

An Ultra-Mechanosensitive Visco-Poroelastic Polymer Ion Pump for Continuous Self-Powering Kinematic Triboelectric Nanogenerators

Repeatable replication method with liquid infiltration to fabricate robust, flexible, and transparent, anti-reflective superhydrophobic polymer films on a large scale

Hee Jae Hwang

Papers

Nanopillar-array architectured PDMS-based triboelectric nanogenerator integrated with a windmill model for effective wind energy harvesting

Exo-shoe triboelectric nanogenerator: Toward high-performance wearable biomechanical energy harvester

Universal biomechanical energy harvesting from joint movements using a direction-switchable triboelectric nanogenerator

An Ultra-Mechanosensitive Visco-Poroelastic Polymer Ion Pump for Continuous Self-Powering Kinematic Triboelectric Nanogenerators

Repeatable replication method with liquid infiltration to fabricate robust, flexible, and transparent, anti-reflective superhydrophobic polymer films on a large scale