Increasing the Range of Wireless Power Transmission to Stretchable Electronics

Wireless power transmission is of paramount importance in stretchable electronics due to the challenges of fabricating effective electrical contacts between stretchable systems and the outside world. Poor stretchable inductor performance has been a major factor limiting the range of power transfer to stretchable systems. Here, through the development of stretchable inductors with the highest quality factors on record (as high as 174, more than double the highest previously demonstrated), we are able to increase the range of effective power transfer to stretchable electronics. Our stretchable inductors were fabricated using liquid-metal-filled channels in a soft silicone and can withstand strains up to 100%. Using this approach combined with magnetic resonance techniques, we show systems able to transfer power effectively at distances of one and two coil diameters, significantly beyond the half-coil diameter distance that was the previous state of the art. Using optimized designs, we demonstrate the efficiency of 64% at one coil diameter (40 mm) and a second system with the efficiency of 15.5% at two coil diameters (84 mm).