Sustainable reutilization of MnO2 from disposable alkaline batteries for microbial fuel cell applications

The increasing energy demand is driven by population growth and the needs of industries for sustainable solutions. However, current energy storage options have limitations, such as high costs and waste. Hence, we focused on creating low-cost, recyclable energy devices using wastepaper cups. Paper pulp acts as a separator, aiding air cathode reactions, whereas a Pt-coated carbon cloth cell (Pt/C) wraps around the cup. Standard paper cup biobatteries, that is, microbial fuel cells (PC-MFCs), reached a power density of 231.56 mW/m³. The results showed that the 3-PC-MFC (3 g/cm² catalyst) achieved 757 mW/m³. The 2-PC-MFC (2 g/cm²) followed with a value of 229.56 mW/m³, and the 1-PC-MFC (1 g/cm²) had a value of 180.59 mW/m³. Although the Pt cathode had the highest power density, the spent battery cathode in the 3-PC-MFC was 3 times more powerful. Increasing the catalyst loading also significantly increased the power output. Finally, when PC-MFCs are interconnected, they directly supply power to various digital clocks with 3 PC-MFCs. This study demonstrates the feasibility of using "dead" batteries to generate electricity directly from wastewater, opening doors for practical applications soon. • A wastepaper cup was used as a cheaper separator in the microbial fuel cell (MFC). • MnO 2 from used batteries is a key cathode catalyst in MFCs. • Pt/carbon cloth cathode in a typical wastepaper cup improved MFC performance. • The practical application of MFC is demonstrated.