Exploring the Sodium‐Storage Mechanism of Nanosized Disodium Rhodizonate as the Anode Active Material

Nanosized disodium rhodizonate (Na2C6O6 , NCO) prepared by antisolvent crystallization is tested as an organic anode material for sodium-ion batteries (SIBS). A reversible capacity of 230 mAh g(-1) combined with an excellent capacity retention of approximate to 85% after 1000 cycles versus Na/Na+ is demonstrated in a NaPF6 -DME electrolyte. Such a promising electrochemical performance is achieved by the synergy of the NCO particle nanosizing, and the formation of a thin, but stable and Na+-permeable solid electrolyte interface layer that builds-up readily in the NaPF6 -1,2-dimethoxyethane electrolyte. The feasibility of the nanosized NCO anode for SIBs is also confirmed in a full sodium-ion cell versus Na3V2(PO4)(3) cathode, and the discharge potential is as high as 2.0 V suggesting a promising energy density.