Topmost Atomistic Li Structures and Native Point Defects in the Li (001) Surface

Abstract

To elucidate the atomic scale mechanism of the dendrite growth in the Li metal anode under the electrochemical condition, the formations of native point defects and topmost atomistic Li structures in the surface of Li metal were studied by using the first-principles calculation. In the (001) surface, vacancies are dominant and mainly confined in the surface, and moreover, the vacancy clustering is not favorable. Li interstitials near the surface always migrate to the top of the surface. Such native point defects without clustering effects near the surface, therefore, cannot be the initial step of dendrite growth. On the surface, the formations of atomistic Li structures with low coordination numbers, such as bridge-, tetrahedron-, pyramid-types and c-directional chain structures, were studied. It is found that the local electric potentials deviation of ~1V can initiate filamentary type dendrite growths in the electrochemical charging process of rechargeable batteries.