Anti-stress ball energy harvester

Abstract Advances in flexible energy harvesters, via converting the ambient energy into electricity, have highly motivated to realize self-powered flexible electronics. However, the requirements for higher current output have been still an urgent challenge for soft energy harvesters. Herein, we present a new type of magnetoelectric soft sphere (MSS) with a portable pluggable interface, which is capable of mechano-electrical conversion via external forces in arbitrary directions, such as hand pressing or gripping. The MSS is composed of liquid metals, magnetic Nd2Fe14B particles and Ecoflex elastomer. Notably, the MSS can break the limitation of saturated surface charge density, resulting in a current density as high as ~10 A/m2. As an anti-stress ball generator, the handheld MSS when repeated compression not only successfully triggers the luminescence of a commercial red LED and the display of an LCD, but also enables the normal working of a calculator. Our study provided here will open new avenues for the design of fully-flexible energy harvesters to convert surrounding mechanical energy to electricity.