Enhanced Sodium-Ion Mobility and Electronic Transport of Hydrogen-Incorporated V₂O₅ Electrode Materials

Although α-V₂O₅ as an attractive electrode material for electrochemical energy storage devices exhibits a high theoretical capacity, its atomic structure with the confined size of channels for Na-ion transport and low electronic conductivity lead to the poor rate performance. Here we demonstrate that hydrogen incorporation in α-V₂O₅ is an effective way to improve the kinetics of ionic and electronic transports by using the density functional theory. Among various structures of hydrogen-incorporated α-V₂O₅, H₂V₂O₅ presents enlarged diffusion channels along the [010] and [001] directions where the diffusion energy barriers decrease to 0.844 eV (−34.93%) and 1.737 eV (−41.81%), respectively. Improved electronic conductivity is also achieved for H₂V₂O₅ due to the insulator–metal transition attributed by the high concentration of hydrogen atoms. As H₂V₂O₅ has smaller volume expansion occurring during the Na-intercalation process, H₂V₂O₅ at the comparable specific capacity exhibits higher rate capability and cyclability than α-V₂O₅