Physiological fluid-assisted nanostructured NbN@Cu foam supercapacitor towards flexible and biocompatible energy storage applications

Abstract

As the demand for implantable and wearable electronic devices is becoming prevalent, developing flexible and biocompatible energy storage is imperative. In this study, we have successfully fabricated a flexible and biocompatible supercapacitor. We used DC magnetron sputtering to deposit niobium nitride (NbN) on the copper foam (Cu foam) substrate to fabricate NbN@Cu foam. The fabricated NbN@Cu foam electrodes demonstrate a highly porous structure with uniform distribution of NbN on copper foam substrate. The in-vitro biocompatibility of the electrode was assessed using cell viability studies on the L929 fibroblast cells. The biocompatibility tests revealed no significant cytotoxic effects on the cell lines. The supercapacitor device demonstrated excellent electrochemical stability and efficient electrochemical performance (specific capacitance of 10.772 Fg−1 and 86.8 % retention after 5000 cycles). The device can operate in various physiological fluids (phosphate buffer saline and cell culture medium). These findings strongly suggest that the NbN@Cu foam supercapacitor holds significant promise as a flexible, and biocompatible energy storage device that can be used in a wide range of applications in wearable and implantable electronic devices.