This paper presents an asymmetric micro Li-ion capacitor which is the integration of a supercapacitor electrode and a Li-ion battery electrode. It exploits the power of supercapacitor and the capacity of Li-ion battery, together with an extended cell potential. Activated carbon (AC) of the supercapacitor material is used to construct the positive electrode, graphite of the anode material in Li-ion battery is adopted in the negative electrode, and an electrolyte used in Li-ion battery, 1 M LiPF6 in organic solvent serves as the electrolyte in the device. The micro three-dimensional (3D) electrodes with separator are fabricated by using micro electro mechanical systems (MEMS) fabrication technology. A pre-lithiation of graphite electrode is then carried out to reduce the electrolyte needed when packaging the prototype and improve its performance. Measurements show that the Li-ion capacitor prototype with 100-mu m-thick interdigital electrodes has a capacity of 180 mu A h/cm(2) and an energy density of about 1750 mJ/cm(2) at a charge/discharge current of 0.5 mA/cm(2). The energy density is much higher than the symmetric AC supercapacitor at the same size. (C) 2015 Elsevier B.V. All rights reserved.