Lithium-based and sodium-based batteries and capacitors using metal foil current collectors, coated with porous layers of particles of active electrode materials for producing an electric current, may adapted to produce heat for enhancing output when the cells are required to periodically operate during low ambient temperatures. A self-heating cell may be placed in heat transfer contact with a working cell that is temporarily in a cold environment. Or one or both of the anode current collector and cathode current collectors of a heating cell may be formed with shaped extended portions, uncoated with electrode materials, through which cell current may be passed for resistance heating of the extended current collector areas. These extended current collector areas may be used to heat the working area of the cell in which they are incorporated, or to contact and heat an adjacent working cell.