Long-Life Na3V2(PO4)3||Graphite Energy Storage Device Enabled via Regulating the Area Density of Anode

The regular graphite can only provide the negligible capacity for Na-ion intercalation, due to the narrow layer spacing and unstable thermodynamic factor. In this study, an energy storage device is created using the prelithiated graphite and Na3V2(PO4)3&NaClO4-based electrolyte, achieving an initial energy density of 317 W h kg−1 and a long lifespan of 1000 cycles with a 71.3% energy retention under the current rate of 1 C. Additionally, the prelithiated graphite anode could be recognized as an artificial Li metal with a strong skeleton, which reduces the volume changes and provides the growth substrate for Na-ion storage by the plating/stripping behavior. When the Li is depleted by participating in the reconstruction of SEI and the occurrence of complex side reactions, the battery system would die as a result. Therefore, the amounts of excess Li have a significant impact on the electrochemical performance of this device. That is to say that regulating the area density of anode enables a long-life Na3V2(PO4)3||graphite energy storage device.