Dissociation of (Li 2 O 2 ) 0,+ on graphene and boron-doped graphene: insights from first-principles calculations.

Reducing charge overpotential is of great significance to enhance the efficiency and cyclability of Li-O(2)batteries. Here, a dramatically reduced charge overpotentialviaboron-doped graphene as a catalytic substrate is successfully predicted. By first-principles calculations, from the perspective of reaction thermodynamics and kinetics, the results show that the electrochemical oxidation of the Li(2)O(2)(+)cation is easier than the chemical oxidation of the neutral Li(2)O(2)molecule, and the oxidation of (Li2O2)(0,+)is facilitated by boron-doping in pristine graphene. More importantly, the results reveal the oxidation mechanism of (Li2O2)(0,+): two-step dissociation with the LiO(2)molecule as a reactive intermediate has advantages over one-step dissociation; the rate-determining step for the dissociation of (Li2O2+)(G)is the oxygen evolution process, while the lithium removal process is the rate-determining step for the dissociation of (Li2O20)(G), (Li2O20)(BG), and (Li2O2+)(BG).