Flexible, large-area, recyclable, decoupled dual sensing of temperature and pressure enabled by mechanically-electrically hybrid networks

Thin, conformable electronic skin (e-skin), capable of accurately perceiving various stimuli (e.g., temperature and pressure), is an important building block for various cutting-edge applications, including human healthcare, structural health monitoring, human-machine interfaces, and closed-loop device systems. However, crosstalk from multiple input signals severely deteriorates the sensing accuracy of the measured temperature and pressure. Moreover, different constituent materials and fabrication protocols utilized for flexible sensors hinder their integration towards multifunctional e-skin. Here, this work introduces mechanically and electrically hybrid networks (MEHNs) in functional nanocomposites for large-area, multiplexed, and decoupled sensing. The rigid, high-resistive vanadium oxide (VO2) microparticles with metal-insulator transition combined with soft, low-resistive liquid metal particles (LMPs) in MEHNs serve as temperature sensing units and mechanical buffers, respectively, leading to an ultra-high yet pressure-insensitive temperature coefficient of resistance (TCR) of −2.23%. Modifying VO2 microparticles with silver nanoparticles to cancel the high TCR is combined with a porous structure to render the nanocomposite with temperature-insensitive pressure sensing with a sensitivity of 1.212% kPa−1. The same constituent material and fabrication protocol of the MEHN nanocomposites, along with their scalability and recyclability, can afford low-cost, large-scale, and multiplexed e-skin for broad application opportunities, including human and battery health monitoring, soft electrical impedance tomography, and robotic perception. Electronic skins are capable to monitor stimuli such as temperature and pressure, though they are susceptible to crosstalk diminishing sensitivity. Here the authors report a mechanically and electronically hybrid network using vanadium oxide and liquid metal particles to optimize selectivity and sensitivity.