A novel sandwich-like MnO ₂ /g-C ₃ N ₄ nanocomposite (NC) based on the integration of high-density MnO ₂ nanorods (NRs) onto the surfaces of two-dimensional (2D) g-C ₃ N ₄ sheets has been successfully fabricated through a facile soft chemical route at low temperature. The MnO ₂ /g-C ₃ N ₄ NC electrode enhanced the supercapacitor (SC) performance, benchmarked against both the bare MnO ₂ NRs electrode and the MnO ₂ /graphene oxide (GO) NC electrode, exhibiting high specific capacitance of 211 F/g at a current density of 1 A/g, with good rate capacity and cycling stability. The sandwich-like hybrid structure, the unique 2D structure of the g-C ₃ N ₄ sheets and the presence of nitrogen in the g-C ₃ N ₄ all contributed to the promising SC performance of the MnO ₂ /g-C ₃ N ₄ NC. This work demonstrated the advantages of the g-C ₃ N ₄ sheets over the commonly-used GO sheets in the design of novel hybrid composite for enhanced capacitance performance of MnO ₂ -based electrochemical SCs, and the results could be extended to other electrode materials for SCs.