Lithium Polysulfide Catalytic Mechanism of AlN/InN Heterojunction by First-Principles Calculation.

To solve the shuttling effect and transformations of LiPSs in lithium–sulfur batteries, heterostructures have been designed to immobilize LiPSs and boost their reversible conversions. In this paper, we have constructed AlN/InN heterojunctions with AlN with a wide band gap and InN with a narrow band gap. The heterojunctions show metallic properties, which are primarily composed of 2s, 2p N atoms and 5s, 5p In atoms. InN has relatively higher adsorptivity for LiPSs than AlN. Reaction profiles show that on the surface of AlN, there is a lower rate-limiting step than on that of InN, from S₈ to Li₂S₆, and a higher rate-limiting step from Li₂S₄ to Li₂S₂, which is more favorable for InN during the reduction from Li₂S₄ to Li₂S₂. The heterojunction can realize the synergistic reaction of trapping–diffusion–conversion for LiPSs, in which AlN traps large Li₂S₈ and Li₂S₆, the heterojunction causes the diffusion of Li₂S₄, and InN completes the conversion of Li₂S₄ to Li₂S. [ABSTRACT FROM AUTHOR]