Polyampholyte saturated with simulated-body-fluid as a flexible, stretchable and self-healing gel electrolyte for biocompatible energy storages and capacitive circuit elements

As implantable electronic medical devices (IEMDs) develop, biocompatible polymer materials with body-friendly non-toxic nature are receiving great amount of attention. Polyampholyte hydrogels have mechanical flexibility and self-healing properties, as well as biocompatibility; thus, it can be applied in various implantable medical devices and wearable devices. In this study, the possibility of using a polyampholyte hydrogel saturated with simulated body fluid (PA-SBF) as the gel polymer electrolytes for energy storage devices and capacitive circuit elements of IEMDs is investigated. At the normal body temperature (35 °C), the PA-SBF exhibited high ionic conductivity of 17.6 mS cm−1 with negligible electron leakage. The supercapacitor fabricated with the PA-SBF gel electrolyte sandwiched between carbon-based electrodes showed an excellent areal capacitance of 219.6 mF cm−2 with a maximum potential window of 1.6 V. The self-healing properties and cytotoxicity of the PA-SBF gel electrolytes were examined as well. With high performance, flexibility, and self-healing property, the biocompatible PA-SBF gel electrolyte can be considered as a promising candidate for the electrolyte of electrochemical devices, energy sources and capacitive circuit elements of future IEMDs.