Exploring high-performance anodes of Li-ion batteries based on the rules of pore-size dependent band gaps in porous carbon foams

Abstract

Porous carbons have long been used in the field of Li-ion batteries (LIB); the disorder of the pore alignment, however, limits the performance. Here, we theoretically design more than 120 carbon foams (CFs), in which ordered one-dimensional nanopores are surrounded by interconnected graphene nanoribbons (GNRs). First-principles calculations demonstrate that these CFs exhibit good stabilities and pore-size dependent electronic properties, which are related to the size-dependent band gaps of GNRs. This gives clues for designing metallic CF networks, which provide a high electronic conductivity for anodes. Further using these CFs as anode materials of LIBs, it is found that 6612Z_S_IV&III(4) is a competitive candidate. The fully lithiated structure only leads to a 1.67% volume change, indicating an excellent cycling stability. What's more, the Li-ions strictly diffuse along the 1D pores with energy barriers less than 0.18 eV; combined with the metallicity, a high rate capacity could be expected. Our results reveal the potential applications of CFs in LIBs with high performances, as well as in electronic devices due to the excellent electronic properties.