The present invention discloses multi-functional electrode (MFE) devices for fast-charging of energy-storage devices. MFE devices include: a multi-functional electrode (MFE) device for fast-charging of energy-storage devices, the device including: a first MFE structure for forming a suitable electrochemical half-couple, the first MFE structure having a first fast-charging component (FCC) and a first MFE assembly; a counter-electrode structure for forming a complementary electrochemical half-couple to the first MFE structure; and an internal voltage controller (IVC) for applying a bias potential to the first MFE structure and/or the counter-electrode structure, whereby the bias potential is set in accordance with the chemical nature of the first MFE structure and the counter-electrode structure. Preferably, the IVC is configured to regulate an intra-electrode potential gradient between the first FCC and the first MFE assembly, thereby controlling a charge rate from the first FCC to the first MFE assembly.