Applied Surface Science, Vol.475, 151-157, 2019
Structure stability and high Li storage capacity of the unzipped graphene oxide monolayer
Density functional theory based calculations are used to investigate the energetically and dynamically most stable structure for a crystalline unzipped graphene oxide (UGO) monolayer by considering parallel or anti-parallel dipolar structures. The O atom in the UGO monolayer induces electron excessive and deficient regions, which makes Li-ions selectively trapped in the electron deficient region. Apart from this, the periodic injection of O in graphene (C4O) opens a small band gap (0.6 eV) while keeps the Dirac cone. The adsorption of Li-ions makes it metallic by donating an extra electron to the UGO monolayer. The UGO monolayer can have a high Li storage capacity of 419 mAh/g and a typical anodic open circuit voltage range of 0.94-0.19 V. The energy barrier for Li migration is almost double of the pristine graphene, which results from the localized positive charge regions in the UGO monolayer.