First-principle study on catalytic activity of functionalized Ti3C2 MXene as cathode catalyst for Li–O2 batteries

Two-dimensional layered Ti3C2, one representative MXene, is notable as promising cathode catalyst for rechargeable lithium-oxygen (Li–O2) batteries. Using first-principles calculations, we construct cathode electrochemical interface catalytic model to simulate the structural evolution during discharging and charging processes, and the calculated ORR, OER and TOT overpotentials are used to quantitatively assess the catalytic activity of Ti3C2 MXene with and without O, F and OH functional groups. Interestingly, we find that the catalytic activity follows such a trend: Ti3C2O2>Ti3C2F2>Ti3C2(OH)2>Ti3C2, which suggests that O-terminated Ti3C2 MXene has great advantages and potentiality for catalyzing ORR and OER in Li–O2 batteries. This is caused by Ti3C2O2 surface shows stronger oxidation capability toward O22− compared to Ti3C2F2, Ti3C2(OH)2 and Ti3C2. The present study may provide a guideline to accelerate ORR and OER reactions of Ti3C2 MXene as cathode catalyst in Li–O2 batteries, with O-terminated group being taken into consideration.