Glyme-Based Electrolyte for Na/Bilayered-V2O5 Batteries

Due to its large interlayer space and multivalent redox capability, bilayered-V 2 O 5 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-V 2 O 5 (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 V 2 O 5 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.