Is graphite nanomesh a promising anode for the Na/K-Ions batteries?

Abstract

Nowadays, the development of promising anodes for Na and K ion batteries (NIB and KIB) has got great attention due to their sustainable and renewable energy applications. Graphite is a good candidate but suffers from low Na (<35 mAhg−1) and K ion storage capacities (∼274 mAhg−1) in the experiments. In this paper, based on the first-principles calculations, we demonstrate that graphite nanomesh with the hole density of 46% (GN46) is a promising anode material for both the NIB and KIB. Remarkably, there are 361–482 mAhg−1 ion storage capacity for the NIB and 482–602 mAhg−1 ion storage capacity for the KIB in the GN46. The in-plane diffusion barriers of Na and K ions are calculated as small as 0.59 and 0.19 eV, respectively. Besides, the holey structure opens an additional out-plane diffusing channel with only 1/14 and 1/10 of the diffusion barrier of those in graphite for Na and K ions. These diffusing properties suggest an improved rate capacity for batteries. Finally, the GN46 shows relatively small superficial area change ratio of less than 3% during the charging process, implying safety in applications. Hence, graphite nanomesh is a promising anode for the NIB and KIB.