context: Using density functional theory (DFT), we calculated the free energy of hydrogen (ΔGH) on various coating materials as well as their electronic conductivity, and used these two parameters to screen for the best candidate material. Materials with suitable hydrogen adsorption (neither too strong nor too weak) located at the top of volcano plots would have optimum activity. Hence, materials with either very strong (highly negative −ΔGH) or very weak bonding (highly positive +ΔGH) should be ideal candidates to suppress the HER. The high ΔGH of Al2O3 (Fig. 1b) suggested its suitability whereas TiO2, despite its high ΔGH, became highly catalytic towards the HER once lithiated into LiTi2O4 (as characterized by a low ΔGH). This increased catalytic activity according to the degree of lithiation might explain why LTO in non-aqueous batteries effectively catalyzed the decomposition of trace H2O present in electrodes and electrolyte. With a highly negative ΔGH, ZnO would also serve as a good candidate for HER suppression. However, its high electronic conductivity accelerated the charge transfer between the electrolyte and electrodes, which kinetically favors the electrochemical reduction of water. Conversely, Al2O3 had a large bandgap (5.33 eV) (Fig. 1c), which suggested very poor electrical conductivity that prevented charge transfer, in sharp comparison with the bandgaps of lithiated LiTi2O4 (0 eV) and ZnO (1.48 eV), respectively. In fact, the latter two were well known for their metallic and semiconducting behaviors (Fig. 1d and S1†). Therefore, the insulator Al2O3 would be the best candidate surface for HER suppression.