Li Diffusion through the Doped and Defected Graphene

Deya Das, Seungchul Kim, Kwang-Ryeol Lee, Abhishek K. Singh 
 

We investigate the effect of nitrogen and boron doping on Li diffusion through the defected graphene using first principles based density functional theory. While high energy barrier rules out the possibility of Li- diffusion through the pristine graphene, the barrier reduces with the incorporation of defects. Among the most common defects in pristine graphene, Li diffusion through the divacancy encounters lowest energy barrier of 1.34 eV. The effect of nitrogen and boron doping on the Li diffusion through doped defected-graphene sheets has been studied. N-doping in graphene with monovacancy reduces the energy barrier significantly. The barrier reduces with the increasing number of N atom. On the other hand, for N doped graphene with divacancy, Li binds in the plane of the sheet, with enhanced binding energy. The B doping in graphene with monovacancy leads to enhancement of the barrier. However, in the case of B-doped graphene with divacancy, barrier reduces to 1.54 eV which could lead to good kinetics. The barriers do not change significantly with B concentration. Therefore, divacancy, B and N doped defected graphene emerge as better alternative to pristine graphene as anode material for Li ion battery.