Glyme-Based Electrolyte for Na/Bilayered-V₂O₅ Batteries

Due to its large interlayer space and multivalent redox capability, bilayered-V2O5 is a very interesting host material for sodium metal batteries. However, the severe capacity fading upon cycling occurring with conventional organic carbonate-based electrolytes largely prevents its application. Herein, we report the outstanding performance of a Na-metal battery using GO/bilayered-V2O5 (GVO) composite positive electrode in glyme-based electrolyte. The battery shows excellent cycling stability benefiting from the stabilization of the Na metal anode due to the use of the glyme-based electrolyte, yielding to low polarization of the negative electrode as revealed via three-electrode cells tests. Interestingly, the cycle performance of presodiated-GVO//GVO (symmetric) cells suggests that the intercalation/deintercalation is a very stable process also in conventional carbonate electrolyte, which is in contrast with previous reports proposing the intrinsic fading of V2O5 electrodes. Overall, the results demonstrate that the stabilization of the Na metal anode/electrolyte interface is the critical step to improve the cycling performance of Na-metal batteries using vanadium oxide-based cathodes.