Fig. 7.

Quantum capacitance C_Q for different MoS₂/Graphene heterostructures. a–b Quantum capacitances calculated from the classical model C_Q^CM(μF cm⁻²) and from the DOS profile of ab initio calculations C_Q^DFT(μF cm⁻²) as a function of the external field E_ext (V nm⁻¹) for various MoS₂/Graphene vdWHs, respectively. The quantum capacitance increase more under negative electric field than positive field. Both classical and DFT calculations show similar trends of relationship between layer numbers and quantum capacitance: the layer numbers of MoS₂ contributes more to the total quantum capacitance than graphene under strong electric field, consistent with the findings of layer-dependent dipole moment and charge transfer