Enhanced Li capacity in functionalized graphene: A first principle study with van der Waals correction

TL;DR

This study uses first-principles calculations with van der Waals corrections to show that functionalized graphene oxide can adsorb lithium with a positive lithiation potential, leading to high specific capacity for battery anodes.

Contribution

It introduces a novel approach to achieve positive lithiation potential on functionalized graphene oxide, surpassing capacities of defect-rich graphene.

Findings

Positive lithiation potential on epoxy and hydroxyl functionalized graphene.

Achieved a high specific capacity of ~860 mAh/g.

Functionalized graphene oxide is more stable than defect-rich graphene for Li storage.

Abstract

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.