First-Principles Studies on the Structural Stability of Spinel ZnCo(2)O(4) as an Electrode Material for Lithium-ion Batteries

Systematic first principles calculations were performed for ZnCo(2)O(4) to clarify its structural and electronic properties, and particularly the structural stability as an electrode material for lithium-ion batteries. For samples with low Li concentration, e.g., Li(n)ZnCo(2)O(4) with n < 1, Li atoms take the center of oxygen octahedra and may diffuse rapidly. Structure distortions and volume expansions can be observed in Li(n)ZnCo(2)O(4) with n > 1 and amorphous structures eventually prevail. The AIMD simulations for Li(9)ZnCo(2)O(4) suggest the formation of Li(2)O, Co(3)O(4) and LiZn local compounds or alloys. In particular, the formation of Zn-Co aggregations and the losing of ZnO pairs are identified as the possible reasons that are responsible to the Li capacity fading in ZnCo(2)O(4) anodes.