A humic acid-bonded metal foil current collector in a battery or supercapacitor, comprising: (a) a thin metal foil having two opposed but parallel primary surfaces; and (b) a thin film of humic acid (HA) or a mixture of HA and graphene, having hexagonal carbon planes, wherein HA or both HA and graphene are chemically bonded to at least one of the two primary surfaces; wherein the thin film has a thickness from 10 nm to 10 μm, an oxygen content from 0.01% to 10% by weight, an inter-planar spacing of 0.335 to 0.50 nm between hexagonal carbon planes, a physical density from 1.3 to 2.2 g/cm3, all hexagonal carbon planes being oriented substantially parallel to each other and parallel to the primary surfaces, exhibiting a thermal conductivity greater than 500 W/mK, and/or electrical conductivity greater than 1,500 S/cm when measured alone without the metal foil.