Oxidation energies of shuttle molecules candidates in lithium-ion batteries from double-hybrid models

As promising candidates for protecting against both overcharge and overdischarge of lithium-ion batteries, the shuttle molecules should be named. Considering the action mechanism of these molecules, it is turned out that their oxidation energies are important factors. Alongside the experimental efforts, computational chemistry within density functional theory (DFT) can play imperative roles in this respect. In the present contribution, in order to predict the oxidation energies of shuttle molecules the double-hybrid (DH) approximations from DFT are of concern. In particular, applicability of the recently proposed DHs including parameterized, parameter-free, and spin-opposite-scaled functionals is evaluated for our purpose. With more or less different accountabilities of the DHs under study, it is revealed that from the parameterized and parameter-free approximations, the B2-PLYP and Perdew-Burke-Ernzerhof (PBE)-cubic integrand DH (CIDH) functionals, respectively, have the lowest deviations while the SOS0-PBE0-DH is the winner against others within the category of spin-opposite-scaled DHs. Perusing the role of both nonlocal exchange and correlation contributions in the energy expression of DHs on the predicted oxidation energies unveils that the high fractions of these terms do not guarantee better performance, but an appropriate proportion between the two is needed to achieve a reliable accuracy. Although this study ascertains the efficiency of DHs for describing the oxidation energies of shuttle molecules candidates, we hope that our findings can function as an inspiring avenue to develop novel DH approximations with a broad range of applications in electrochemistry.