▎ 摘　　要

The effect of co-dopants (N, P, and S) and transition metals (TMs = Ti, V, Cr, Mn, Co, Ni) presence in mono- and multilayer graphene on the final material geometry, stability, electrical and magnetic properties, and quantum capacitance was systematically investigated using density functional theory (DFT) calculations. The simultaneous presence of dopants and vacancies is more effective than doping alone in enlarging the quantum capacitance of graphene. Incorporation of N, P, and S co-dopants and TMs-dopants significantly improved the quantum capacitance and surface charge storage of graphene. The co-doping of Ti and N/P/S systems are the most outstanding, with the highest quantum capacitance of 239.84 mF/cm(2). However, due to the interaction between layers, the quantum capacitance of multilayered co-doped graphene is lower than the capacitance of similarly-doped monolayered graphene. The results demonstrated in this work provide insights on the effective approach of the quantum capacitance enhancement of graphene-based supercapacitor. (C) 2020 Elsevier Ltd. All rights reserved.