Sustainable Power Generation with an All-Silk Electronics-Based Yeast Wearable Biobattery

Transient electronics, designed to disintegrate in a controlled manner after their useful life, have been proposed as a solution to mitigate the ecological and health impacts of electronic waste (e-waste). Despite this innovative approach, which has seen significant application in biologically integrated sensors and therapeutic devices, it still results in the accumulation of different materials and nanomaterials for the powering systems often based on batteries, which themselves contribute to the e-waste problem. Here, we explore the use of the silk cocoon from Bombyx mori as a key component in the development of environmentally friendly all-silk electronics-based biobatteries. The approach focuses on employing Saccharomyces cerevisiae to generate electroactive extracellular polymeric substances, which serve as the anode material within the biobattery. The silk cocoon's natural properties are utilized for the membrane in both anodic and cathodic compartments, with potassium ferricyanide embedded within the silk fibroin acting as the cathode. By coupling three modules in series, ohmic loss is minimized, preserving the voltages of each module. This setup allows a biobattery with discharge at a voltage over 1.1 V, demonstrating its potential to deliver stable and sufficient power for applications. The biobattery demonstrated a 95.2% utilization of recyclable materials for housing, membrane, and electrode components and a 95.6% utilization of biodegradable components for the electrolyte, offering a promising pathway for the advancement of eco-friendly energy storage solutions.