Flexible solid-state Zn-polymer batteries with practical functions

Abstract The skyrocketing progress of wearable electronics has urged the development of advanced batteries that can adapt to various conditions in practical applications, such as mechanical impact, bending, cutting, or freezing. Herein, solid-state rechargeable Zn-ion batteries (ZIBs) based on the poly(4,4′-oxydiphenol)-modified nanoporous carbon cathode is presented. By using an anti-freeze gelled electrolyte, the sandwich-structured flat cell exhibits stable electrochemical performance under mechanical impact and good working condition after being partially cropped. Also, the device being cut into halves can be re-connected to resume its powering function, showing a self-healable behaviour. Our temperature-dependent tests from 25 to –20 °C reveal that the operating voltage window of the solid-state ZIB can be widened at low temperatures, thus increasing the capacity despite of the reduced redox activity of the polymer electrode. Even the device capacity at –25 °C is a bit higher than that at room temperature. In addition, the ZIB delivers a flat discharge plateau around 1.15 V, higher than those of most other Zn-organic cells ever reported. To understand the charge storage mechanism, the H+ and Zn2+ co-insertion mechanism is investigated by combing theory with experiment.