Theoretical study on the heterostructures of MXenes and B-doped graphene as promising anode materials for lithium-ion batteries

In this work, using first-principles calculations, we systematically investigated the geometric and electronic properties of heterostructures composed of two different structures, i.e., M2CO2 (M = Sc, Ti, V) and B-doped graphene (BDG), and further investigated their Li storage mechanisms and properties. Our results show that an obvious electron transfer occurs between the interfaces of the heterostructure, which is determined by the difference of the work function between the individual structures. Compared with the individual structures, the adsorption of Li on the heterostructures was enhanced, and the theoretical capacitance was found to have increased accordingly. We propose two mechanisms that explain these behaviors, i.e., the effect of electron transfer between heterostructure interfaces, and the synergistic adsorption effect with the upper and lower individual layers. In addition, we also found that B-doping of the graphene layer enhanced the Li adsorption and reduced the Li diffusion energy barrier in the heterostructure. These findings provide valuable insights into the development and application of heterostructures for lithium-ion battery applications.