The present disclosure relates to surface-functionalized carbonaceous particles, optionally in agglomerated form, methods for making such surface-functionalized carbonaceous particles and their use, for example as conductive additives in battery electrodes. The surface-functionalized carbonaceous particles are for example obtainable by milling a non-graphitic carbon material, followed by subsequent functionalization through controlled oxidation. The surface-functionalized carbonaceous particles can be used as additive in battery electrodes. The disclosure also pertains to dispersions of such carbonaceous materials in a liquid medium and their use as, among others, conductive coatings. Polymer compounds filled with the surface-functionalized carbonaceous particles are also disclosed.