In the present work, asymmetric supercapacitors (ASCs) are assembled using a highly conductive N-doped nanocarbon (NDC) material derived from a polyaniline hydrogel as a cathode, and Ni foam covered with flower-like Co3O4 nanosheets (Co3O4-Ni) prepared from a zeolitic imidazolate metal-organic framework as a single precursor serves as a high gravimetric capacitance anode. At a current of 0.2 A g(-1), the Co3O4-Ni electrode provides a gravimetric capacitance of 637.7 F g(-1), and the NDC electrode provides a gravimetric capacitance of 359.6 F g(-1). The ASC assembled with an optimal active material loading operates within a wide potential window of 0-1.1 V, and provides a high areal capacitance of 25.7 mF cm(-2). The proposed ASC represents a promising strategy for designing high-performance supercapacitors. (C) 2017 Elsevier B.V. All rights reserved.