Technology Outline (Process Description)

Graphene Oxide (GO) was synthesized by the modified Hummers method, involving the addition of 2g graphite powder (2- 11 µm size) to a solution of HNO3 (13.2 ml, 69%) and H2SO4 (80 ml, 98%) in a 1000 mL flask, followed by continuous stirring for 40 minutes in an ice bath (10-20 °C). Subsequently, 12 g KMnO4 (99%) was added and stirred 2 hours. After removing the ice bath, 100 mL of DI water was added, raising the temperature to 95 °C. Dropwise H2O2 (30%) was added to the solution to quench oxidation, and the solution turned yellow; then, the solution was allowed to settle for 16 hours. GrO residue was obtained by rinsing with HCl (36 %) and DI water, then exfoliated using 24 hours sonication. Thermal reduction of GO (TrGO) at 180°C for 40 min. Porous Si (PS) is synthesized by anodization on a Si wafer, followed by electropolishing to remove the PS film. PS-decorated TrGO was prepared by hand grinding the PS and TrGO in a ratio of 1:4 (weight).