Ab initio insights into Graphene-Zirconium disulfide/diselenide heterostructure as electrode material for alkali-ion batteries

Abstract

In the search for an energy storage medium with higher electronic conductivity, rate performance and moderate volume expansion, van der Waals heterostructures are a promising alternative. Herein, the potential of graphene (Gr) and Zirconium dichalcogenide (ZrX2, X = S, Se) van der Waals heterostructures for applications as battery electrodes is explored using density functional theory (DFT) calculations. Through intercalating alkali ions (Li and K) between the Gr and ZrX2, we obtain low energy activation barriers, indicating that Gr-ZrX2 van der Waals heterostructures can be candidates for high rate performance electrode application. DFT calculations also indicate that the Gr-ZrX2 heterostructure formation is energetically favoured with better volume expansion as compared to bilayer Gr and ZrX2. The calculated open circuit voltage (OCV) for K intercalation was 0.66 V (Gr-ZrSe2) and 0.77 V (Gr-ZrS2), hence suitable for anodic application in Potassium-ion batteries (KIB). The calculated OCV for Li interaction was 2.83 V (Gr-ZrSe2) and 2.95 V (Gr-ZrS2) hence suitable for cathodic applications