Quantum capacitance of surface functionalized MSTe (M = Mo, W) as supercapacitor electrodes

Abstract The electrodes of supercapacitors using two-dimensional materials play an important role in solving energy problems. The atomic structure, quantum capacitance ( C Q ) and surface charge storage ( Q ) of MSTe (M = Mo, W) were explored by density functional theory. The effects of the introduction of S/Te-vacancy and transition-metal dopants (Y, Zr, Ru, Rh, Pd and Ag) on the capacitance behavior of MSTe were also investigated. The results showed that pristine MoSTe showed the highest quantum capacitance value (643.60 μ F cm −2 ), indicating its potential as cathode materials for supercapacitors. The introduction of S/Te-vacancy and dopant atom decreased the maximum C Q values of MSTe substrates under negative bias. Among these, the Ag-doped S-vacancy MoSTe exhibited relative higher C Q (419.33 μ F cm −2 ) and Q (120.39 μ C cm −2 ) values at positive bias, demonstrating it can be used as effective anodes for supercapacitors.