Power supply system in smart contact lens

Abstract

The growing demand for real-time health monitoring has fuelled the development of wearable and implantable technologies. Smart contact lenses is a progressive technology that combines traditional lens with nanotech to provide a range of advanced functionalities and capabilities. However, powering these lenses presents a challenge due to stringent safety, size, and biocompatibility requirements. Hence, the fabrication of a flexible aqueous battery system for powering smart contact lenses has been achieved. The tear-based batteries embedded within the contact lens have been evaluated in terms of electrochemical performance and analysed.

Copper Hexacyanoferrate (CuHCFe) was chosen as the cathode material of the battery and Prussian blue material as the anode. The electrodes and a separator were assembled and encased in hydrogel solution in the form of a contact lens made of silicone material. The integrated lens is cured with UV rays and subjected to electrochemical tests such as the Cyclic Voltammetry (CV) and the Galvanostatic Cycling with Potential Limitation (GCPL), immersed in a solution that mimics the composition of human tear fluids.

The battery performs with a coulombic efficiency of ~76% and a specific capacity of 29 mAh/g in 0.024M of potassium chloride and 0.45M of sodium chloride. Additionally, the concept of wireless charging was briefly investigated and achieved a power transfer of ~85% efficiency.