Discovering Giant Magnetoelastic Effect in Soft Systems for Nanogenerators

Magnetoelastic effect is usually observed in rigid bulky metal alloys. Very recently, we discovered giant magnetoelastic effect in a soft system composed of platinum-catalyzed silicone polymer matrix and neodymium-iron-boron nanomagnets. The soft composite system shows up to four times enhancement of the magnetomechanical coupling factor (T/Pa) than the traditional rigid counterpart owing to a distinct physical mechanism. The giant magnetoelastic effect was further coupled with magnetic induction to invent a soft magnetoelastic nanogenerator as an emerging approach to revive the community of biomechanical energy conversion that is challenged by low current, high internal impedance, and low water/humidity resistance for decent operation stability. This discovery established an alternative way for biomechanical to electrical conversion which could work stably on wet skin or in body fluids without reliance on any encapsulation. We studied its working mechanism by a wavy chain model based on the magnetic dipole-dipole interaction and demagnetizing factor. To facilitate practical applications, we explore their applications as bioelectronics for human-body-centered energy, sensing, and healthcare. For example, we invented a textile magnetoelastic nanogenerator, weaving the 1D soft nanomagnet fibers with conductive yarns, which could used for energy harvesting from human body and convert the arterial pulse into electrical signals.