Coffee Ground Matrix Frame‐Based Transient Battery for Environmentally Sustainable Sensor Applications

Abstract As the demand for sustainable green energy storage solutions surges, eco‐friendly transient batteries emerge as a viable option. This study explores the practical concept of a sustainable transient battery (TB) incorporating coffee ground‐derived biodegradable matrix frames. These frames, combined with a fully biodegradable magnesium alloy (Mg AZ31)‐molybdenum trioxide (MoO 3 ) primary battery, offer a novel approach to environmental sustainability. The transient battery with a sodium alginate electrolyte infused with phosphate‐buffered saline (PBS) yield a stable output voltage of 1.65 V, an extended lifetime of 5 days, and a specific energy density of ≈4.70 mWh cm −2 at ambient temperature, with a discharge capacity of up to 6.05 mAh cm −2 at a current density of 0.05 mA cm −2 . Furthermore, size‐dependent investigations revealed an increase in current density from 5 to 30 mA cm −2 as battery dimensions increased from 0.25 to 2.25 cm 2 . The dissolution process demonstrates complete degradation of the electrodes within 60 days in PBS solution. The integration of transient coffee ground frames significantly enhances the environmental sustainability for the devices by repurposing organic waste into high‐performance electronic components. With these novel features, the proposed battery is positioned as a promising candidate for applications in environmental sensing, low‐power electronics, and sustainable biodegradable devices.