Utilization of Spent Coffee Grounds with Hydrochloric Acid (HCl) as Electrolyte for Bio-Battery Applications

Coffee is a caffeinated beverage that is well known worldwide and its existence continues to grow. Only 10% of coffee is consumed and the rest become spent coffee grounds, previous research has shown that spent coffee grounds can be used as bio-absorbent, bio-diesel and bio-battery. In this study, we will synthesize bio-batteries made from spent coffee ground. This research will treat spent coffee grounds with hydrochloric acid (HCl) at a dilution concentration of 30%, 50%, and 70%, and dried at a temperature of 200°C; 300°C; and 400°C. The result indicated that the variation a HCL dissolution variation of 50% (with combination of all variation of drying) lasted up to 52 days with a maximum power of 0.024 W. Characterization using X-Ray Diffraction (XRD) at variation of 300°C,50% shows peak at 2θ = 28.92°, other variation shows 2θ = 28.32° (200°C,50%), and 2θ = 28.68° (400°C,50%). Morphology of the spent coffee ground (300°C,50%) observed using Scanning Electron Microscope (SEM) EDX, it shows that the structure is in the form of fused flakes like carbon with visible porosity. From these data, spent coffee grounds with treatment of HCl could be considered to be the next-generation electrolyte for batteries in the future.