Chemically Active Reduced Graphene Oxide with Tunable C/O Ratios

Organic dispersions of graphene oxide can be thermally reduced in polar organic solvents under reflux conditions to afford electrically conductive, chemically active reduced graphene oxide (CARGO) with tunable C/O ratios, dependent on the boiling point of the solvent. The reductions are achieved after only 1 h of reflux, and the corresponding C/O ratios do not change upon further thermal treatment. Hydroxyl and carboxyl groups can be removed when the reflux Is carried out above 155 degrees C, while epoxides are removable only when the temperature is higher than 200 degrees C. The increasing hydrophobic nature of CARGO, as its C/O ratio increases, Improves the dispersibility of the nanosheets In a polystyrene matrix, in contrast to the aggregates formed with CARGO having lower C/O ratios. The excellent processability of the obtained CARGO dispersions is demonstrated via freestanding CARGO papers that exhibit tunable electrical conductivity/chemical activity and can be used as lithium-ion battery anodes with enhanced Coulombic efficiency.