Investigation of energy storage in 2D Dion-Jacobson type materials using promised DFT + U approach

The DFT + U study was employed to investigate the Dion-Jacobson phase perovskite RbLaNb₂O₇ for energy storage applications. The compound exhibits thermodynamic stability in the orthorhombic phase, confirmed by negative formation enthalpy values. The electronic analysis reveals semiconducting behavior, enabling photon-induced electron-hole pair generation. Analysis of the mechanical properties indicates that RbLaNb₂O₇ exhibits substantial mechanical stability, suggesting its viability as a candidate material for energy storage applications. Photocatalytic performance was evaluated through mass ratio analysis, while optical properties demonstrated a strong correlation with the internal electronic band configuration. The conduction band edge energy was determined to be −0.258 eV. Partial Bader charge analysis confirms the presence of both ionic and slightly covalent bonding interactions between atomic species. Solar cell efficiency calculations were conducted as a function of thickness to assess photovoltaic applications. RbLaNb₂O₇ demonstrated a solar cell efficiency of 15.96 %. These findings indicate that RbLaNb₂O₇ represents a promising candidate material for optoelectronic device applications, particularly in the context of photovoltaic implementations. Substitution of oxygen atoms with hydrogen atoms was performed to evaluate the hydrogen storage characteristics of the compound. The resulting RbLaNb₂O_7-xH_x demonstrated a gravimetric hydrogen capacity of 3.57 wt%, which meets the target criteria established by the US Department of Energy. Finally, the analyzed results and hydrogen storage capabilities of 2D DJ-type compound indicate that it is appropriate for hydrogen storage and possess the potential to significantly contribute to various energy storage applications.