  Computational chemistry is a powerful tool for the discovery of novel
materials. In particular, it is used to simulate ionic liquids in search of
electrolytes for electrochemical applications. Herein, the choice of the
computational method is not trivial, as it has to be both efficient and
accurate. Density functional theory (DFT) methods with appropriate corrections
for the systematic weaknesses can give precision close to that of the
post-Hartree--Fock coupled cluster methods with a fraction of their cost.
Thence, we have evaluated the performance of a recently developed non-empirical
Strongly Constrained and Appropriately Normed (SCAN) density functional on
electronic structure calculations of ionic liquid ion pairs. The performance of
SCAN and other popular functionals (PBE, M06-L, B2PLYP) among with Grimme's
dispersion correction and Boys-Bernardi basis set superposition error
correction was compared to DLPNO-CCSD(T)/CBS. We show that SCAN reproduces
coupled-cluster results for describing the employed dataset of 48 ion pairs.
