Interaction of Lithium with a Monolayer of Graphene Monoxide

Abstract

The interaction of Li atoms with a graphene monoxide (GmO) monolayer in various Li x C y O y structures is investigated to determine if a monolayer of GmO can bind Li atoms and to predict the maximum theoretical capacity of this potentially new anode material for Li-ion batteries. Density functional calculations show that Li atoms are adsorbed on the GmO monolayer by attaching to the oxygen atoms and that Li atoms tend to repel during lithiation. An isolated Li atom prefers adsorption at the hollow site of the carbon sublattice although the hollow site of the oxygen sublattice, which is close in energy, may be preferable for multilayer systems since it allows Li atoms to move closer to the monolayer; at higher Li concentrations, the Li 2 C 6 O 6 configuration for monolayer GmO is energetically stable while an equivalent configuration for graphene (Li 2 C 6 ) is not, and Li 2 C 2 O 2 (with a theoretical capacity of 957 mAh/g) has a formation energy near zero. Analysis of the band structure and density of states shows that Li donates a large fraction of its valence electron to the GmO although there is also the formation of covalent Li−O bonds, thus facilitating the formation of Li + ions when leaving the GmO monolayer. These characteristics are desirable for the battery anode material and suggest that GmO, especially in the multilayer form, is a promising candidate.

Fast rate lithium metal batteries with long lifespan enabled by graphene oxide confinement

“…36,44 These covalent Li−O bonds are also shown to facilitate the Li + ions formation when leaving the graphene monoxide layer, which could be of substantial 27 benefit for fast charging Li batteries. 36 Li adsorption on GO layer is significantly stronger than its adsorption on the graphene layer due to stronger Li−O bond when compared to Li−C bond 44 and the coexistence of these bonds can further strengthen the GO-Li bond at the interface. Our DFT calculations further illustrate strong affinity of the Li ion to the oxygen-containing groups of the GO layer, which is favored by -1.83 eV.…”

“…It is known that the confinement effect of 2D materials can arise from several synergistic factors such as (1) strong molecular interactions (e.g. van der Waals or covalent bonding) between 2D material and substrate leading to elevated pressures at the nanoscale interface; [36][37][38][39][40][41][42] (2) high mobility of ions on the surface of 2D materials; 36,41,43,44 and (3) high surface area of 2D materials for nucleation and growth of metals. 39,40,42,43 Al Balushi et al 37 reported synthesis of 2D gallium nitride through a migration-enhanced encapsulated growth technique by using epitaxial graphene.…”

“…47,48 It is also known that GO membrane have negatively charged nanopores, which permits the Li ions transport. 1,7,25,[49][50][51][52][53][54][55][56] Radevych et al 36 reported that Li metal donates its valence electron at a significant fraction to the graphene monoxide. The formation of covalent Li-O bonds is shown to facilitate the Li + ions formation when leaving the graphene monoxide layer, which could be of substantial benefit for fast charging Li batteries.…”

“…The formation of covalent Li−O bonds is shown to facilitate the Li + ions formation when leaving the graphene monoxide layer, which could be of substantial benefit for fast charging Li batteries. 36 Dimakis et al 44 reported that Li metal valence electrons could partially hybridize with the graphene layer, forming Li−C and Li−O bonds with some covalent character. They have also shown that Li adsorption on GO layer is significantly stronger than its adsorption on the graphene layer due to stronger Li−O bond when compared to Li−C bond.…”

A new polymorph of graphene monoxide: an all-sp3 bonded metal and ambient pressure superconductor

“…We should also mention that the structure is different from αand β-graphene monoxide phases predicted recently. 13 Carbon sheets of these phases consist of sp 3 -hybridized carbon atoms, connected by double bridges of oxygen atoms and they are dielectric. On the other hand, our structure (which we name γ-graphene monoxide) is totally sp 3 bonded, but is metallic.…”