Utilization of Spent Coffee Grounds with Sodium Hydroxide (NaOH) as Electrolyte for Applications Bio-Battery

Coffee is a drink that is very well known and popular throughout the world. Currently, many coffees produce a large number of spent coffee grounds. Nearly 50% of the world produces coffee, resulting in about 6 million tons of spent coffee grounds per year. This research does on the manufacture of batteries made from spent coffee grounds with the addition of natrium hydroxide (NaOH) with a variation of dissolution of 30%, 50%, and 70% and heating at a temperature of 250°C;350°C; and 450°C. The result is a variation of heating 450°C (with the combination of all variations) resilient in the use of 52 days with 0.0405 W maximum power. Observations were made using the Scanning Electron Microscope EDX. The results of the morphology of the spent coffee grounds have a flake shape that looks like carbon and indicates the presence of porosity in the spent coffee grounds after being given a solvent with a content of Carbon (C) of 62.78%, Oxygen (O) of 30.82%, Sodium (Na) of 6.4%. Characterization using X-Ray Diffraction (XRD) At a temperature of (250°C, 70% concentration) with 2θ is 31.3268°, (350°C,70% concentration) with 2θ is 30.4838º, and (450°C, 70% concentration) with 2θ is 31.6880º. From these data, spent coffee grounds after adding NaOH could be considered an eco-friendly electrolyte material for the world.