Fabrication and Characterization of a Flexible Ag/AgCl-Zn Battery for Biomedical Applications

Abstract

A flexible silver-zinc fabric-based primary battery that is biocompatible, conformable, and suitable for single-use wearable biomedical devices is reported. The planar battery was fabricated by screen printing silver/silver-chloride and zinc electrodes (14 mm × 8 mm) onto a silk substrate. A biologically relevant fluid, phosphate buffered saline was used as a liquid electrolyte for characterization. Cyclic voltammetry, electrochemical impedance spectroscopy, and current discharge properties at constant densities of 0.89 μA/cm2, 8.93 μA/cm2, and 89.29 μA/cm2 were used to quantify battery performance. Nine cells were placed in series to generate a greater open circuit voltage (>6 V) relevant to previously reported biomedical applications. The nine-cell battery was evaluated for operation under mechanical strain due to likely placement on curved surfaces of the body in wearable applications. The nine-cell battery was discharged over 4 h at 8.93 μA/cm2 in an unstrained condition. The mechanically strained battery when mounted to a mannequin to mimic anatomical curvature discharged up to 30 min faster. Additionally, the nine-cell battery was used in an in vitro wound model to power an electroceutical, showing promise towards practical use in active, corrosive, and potentially biohazardous environments.

Keywords

• flexible battery
• silver
• zinc
• biocompatible
• electroceuticals