Stretchable multifunctional self-powered systems with Cu-EGaIn liquid metal electrodes

With the rapid development of wearable electronic devices, higher requirements are pushing forward the overall circuit design of variability, flexibility, and stretchability. However, power supplies and functional circuits with these characteristics are difficult to be implemented with critical challenges. Here, the use of Cu particles mixed liquid metal (Cu-EGaIn) as an easy-to-print electrode provides a feasible strategy to producing a stretchable multifunctional self-powered system, which consists of a liquid-metal-based fully soft triboelectric nanogenerator (TENG), micro-supercapacitors (MSCs) with Cu-EGaIn/MXene composited electrodes, a liquid-metal-based energy management module (PMM), and a functional circuit. We systematically evaluated the electrical performance of each component, achieving the maximum power supplied by the fully soft TENG at 53.57 mW m−2, the specific areal capacitance of the MSC with Cu-EGaIn/MXene electrode at 1.51 mF cm−2, good charge/discharge rate capability and excellent cycle stability (~90 % retention) during the stretching process. In addition, the functional circuit can readily work in a variety of deformations (e.g., stretching, folding, and twisting). The demonstrated stretchable and multifunctional self-powered system with Cu-EGaIn liquid metal electrodes shows great significance in sustainable human-machine interface, self-powered printed circuit board, versatile integrated circuits, etc.