Penta graphene: A Promising Anode Material as the Li/Na Ion Battery with Both Extremely High Theoretical Capacity and Fast Charge/Discharge Rate.
Recently, a new two dimensional (2D) carbon allotrope named penta graphene was theoretically proposed Zhang S. et al. Proc. Natl. Acad. Sci. U.S.A. 2015 112 2372 and has been predicted to be the promising candidate for broad applications due to its intriguing properties. In this work, by using first principles simulation, we have further extended the potential application of penta graphene as the anode material for a Li/Na ion battery. Our results show that the theoretical capacity of Li/Na ions on penta graphene reaches up to 1489 mAh*g 1, which is much higher than that of most of the previously reported 2D anode materials. Meanwhile, the calculated low open circuit voltages (from 0.24 to 0.60 V) in combination with the low diffusion barriers =0.33 eV) and the high electronic conductivity during the whole Li/Na ions intercalation processes, further show the advantages of penta graphene as the anode material. Particularly, molecular dynamics simulation (300 K) reveals that Li ion could freely diffuse on the surface of penta graphene, and thus the ultrafast Li ion diffusivity is expected. Superior performance of penta graphene is further confirmed by comparing with the other 2D anode materials. The light weight and unique atomic arrangement (with isotropic furrow paths on the surface) of penta graphene are found to be mainly responsible for the high Li/Na ions storage capacity and fast diffusivity. In this regard, except penta graphene, many other recently proposed 2D metal free materials with pentagonal Cairo tiled structures may be the potential candidates as the Li/Na ion battery anodes.
ACS applied materials interfaces