Recycled Battery Materials for Green and Sustainable Series and Parallel Microbial Fuel Cell Stacks

The rapid increase in the amount of electronic waste poses a significant environmental challenge, requiring innovative recycling strategies that enable resource recovery while supporting sustainable energy generation. Microbial fuel cells (MFCs) offer a promising solution by integrating recycled materials with organic waste to produce bioelectricity; however, conventional methods rely on chemically intensive processes, which limit their environmental benefits and scalability. This study presents an approach without utilizing harsh chemicals for MFC stack fabrication using depleted D-type Zn-carbon dry batteries and household bio-waste sludge. The work optimizes bio-waste sludge treatment to enhance electrochemical performance in single-chambered, mediator-less MFC stacks. By fine-tuning the sludge treatment temperature, the modified system achieves a 25% increase in power density compared to previous nitric acid–based approaches. The MFC stack reaches a peak power density of 40 mW/m2 in parallel configuration and generates 8.9 V with 10 units connected in series. These findings demonstrate a fully sustainable and scalable solution that combines e-waste recycling and bio-waste utilization for renewable energy applications, contributing to the advancement of eco-friendly MFC technologies.