Influence of the co-doping and line-doping on the quantum capacitance of stanene for supercapacitor electrodes

The influence of co-doping and line-doping of N/P/S and heavy metals (TMs, Ti, V, Fe, Ni) on geometry, stability, electrical properties and quantum capacitance of stanene were systematically investigated by using density functional theory calculations. The results indicate that the quantum capacitance and surface charge storage can be more obviously improved by the line-doping than co-doping. [Display omitted] •The effect of co-doping and line-doping on the quantum capacitance (CQ) of stanene is systematically investigated.•The CQ and Q are more significantly improved by line-doping.•The line-doped of Ti/V and N/P systems are recommended as the cathode material of asymmetric supercapacitors. The effect of co-doping and line-doping of N/P/S and heavy metals (TMs, Ti, V, Fe, Ni) in stanene on the geometric structure, electronic behaviors, and quantum capacitance was systematically studied using density functional theory (DFT). The calculated results suggested that the line-doping enlarged the quantum capacitance (CQ) of stanene more effectively than that of co-doping. The electron density of states indicated the increase of CQ was attributed to the hybridization of TM-dopant and sn-atoms around the Fermi level. However, the performance of quantum capacitance of doped-stanene was at a disadvantage to that of doped-graphene. We hope our results give further insights into the improvement of CQ of stanene-based supercapacitors.