Exploring Highly Reversible 1.5-Electron Reactions (V/V/V) in NaVCr(PO) Cathode for Sodium-Ion Batteries.

The development of highly reversible multielectron reaction per redox center in sodium super ionic conductor-structured cathode materials is desired to improve the energy density of sodium-ion batteries. Here, we investigated more than one-electron storage of Na in NaVCr(PO). Combining a series of advanced characterization techniques such as ex situ V solid-state nuclear magnetic resonance, X-ray absorption near-edge structure, and in situ X-ray diffraction, we reveal that V/V and V/V redox couples in the materials can be accessed, leading to a 1.