  We have investigated the adsorption of Li on graphene oxide using density
functional theory. We show a novel and simple approach to achieve a positive
lithiation potential on epoxy and hydroxyl functionalized graphene, compared to
the negative lithiation potential that has been found on prestine graphene. We
included the van der Waals correction into the calculation so as to get better
picture of weak interactions. A positive lithiation potential suggests a
favorable adsorption of Li on graphene oxide sheets that can lead to an
increase in the specific capacity, which in turn can be used as an anode
material in Li-batteries. We find a high specific capacity of ~860 mAh/g by
functionalizing the graphene sheet. This capacity is higher than the previously
reported capacities that were achieved on graphene with high concentration of
Stone-Wales (75%) and divacancy (16%) defects. Creating such high density of
defects can make the entire system energetically unstable, whereas graphene
oxide is a naturally occurring substance.
