The relationship between the adsorption configuration and fermi energy levels in the conversion process of Li2S6/Li2S8 on the ZrO2 surface

Abstract

The transition metal oxide ZrO2 can clearly adsorb large lithium-sulfur rings (Li2S6 and Li2S8) and exhibits good conversion performance. To study the adsorption strengths of Li2S6/8, the configuration evolution and adsorption energies of Li2S6 and Li2S8 on the ZrO2 surfaces of tetragonal (t-ZrO2), cubic (c-ZrO2), and monoclinic (m-ZrO2) are calculated by a first-principles method. The results show that the Fermi level controls the adsorption and conversion strength. The relationship between the Fermi level in the partial densities of state (PDOS) and the adsorption strength of the large lithium-sulfur ring is studied for the three surfaces formed by the different crystal structures of ZrO2. The crystal structure of ZrO2 can affect the Fermi energy level of S and Zr when Li2S6/Li2S8 adsorbs on the ZrO2 surface. A change from p-type catalysis for Li2S6 and Li2S8 on the t-ZrO2 surface to the N-type catalysis model on the m-ZrO2 surface is established based on the change in the Fermi level. The c-ZrO2 conversion surface, the Fermi energy of which level is located between the valence and conduction bands, has the moderate adsorption energy. Double Li atoms adsorption on the dimer row of O atoms bridge not only leads to ring opening but also breaks the long chain to degrade Li2S6/Li2S8.