Micro-tabless-pouch-cell (MTPC) with high energy density and exposed functional current collector for flexible device

Abstract

Power sources with stable electrochemical performance, flexible integration, and function extensibility are essential to meet the demands for emerging flexible electronics. The simultaneous realization of these properties is challenging based on current solutions for designing flexible batteries. Herein, we develop a new type of design strategy called Micro-tabless-pouch-cell (MTPC), which realizes the miniaturization of pouch cells by replacing the conventional ultrasonic welding protocol with an innovative tab-glue-hot-welding process during sealing. The electrochemical performance of the electrodes in the MTPC is comparable to that of the coin cell, while the weight of the entire MTPC device is reduced by 95%, resulting in a 2230.93% increase in gravimetric energy density (14.242 Wh/kg vs 0.611 Wh/kg). The miniaturization enables the MTPC to be easily integrated on flexible substrates. Moreover, the MTPC has a unique structure of exposed current collector, which enables function extensibility. As a proof of concept, an MTPC with smart self-protection capability upon over-heating is demonstrated by integrating a reversible thermal switch composed of an Ecoflex/ethanol composite. The simultaneous realization of robust electrochemical performance, capability for flexible integration, and function extensibility in MTPC is expected to push the developments for various high-end flexible electronics that require stable input of energy.