Enhanced Li capacity in Defective Graphene and its Allotropes.
Dibakar Datta (Brown University), Junwen Li (University of Pennsylvania ), Vivek Shenoy (The University of Pennsylvania)
Lithium ion batteries: When Chemistry meets Mechanics
Wed 10:45 - 12:15
Salomon 003
Using first-principles DFT calculations, we have studied the Li adsorption on defective graphene and its allotropes. Our results show that Li cannot be adsorbed on pristine graphene on any site for any Li concentration. However, the presence of vacancy and Stone-Wales (SW) defects facilitates the Li adsorption and it is more favorable in the neighborhoods of defects. At low percentage of vacancy defect (6.25%), we cannot get capacity more than 372 mAh/g. With the increase in defect density, more Li adsorption is possible giving high capacity (around 700 mAh/g). However, for each defect density, there is a maximum limit of capacity beyond which the adsorption is not possible. Presence of SW defects shows the same tendency. Graphene full of SW defects can give very high capacity (around 1000 mAh/g). We have extended the study for different graphene allotropes. For each system, we found the increase in capacity until a maximum limit.