Towards a widely operate temperature sodium-ion battery via a new zinc phosphate anode material

The conversion-type materials’ considerable theoretical capacity and appropriate working potential provide a desirable anode for sodium-ion batteries (SIBs). Therefore, the work to develop new high electrochemical performance and low working potential conversion type anode materials has become vital to its practical application in SIBs. Herein, we first use zinc phosphate (Zn₃(PO₄)₂, denoted as ZPO) as anode for SIBs. After modifying via chemical vapor deposition, the carbon coating ZPO (denoted as ZPO@C) as anode exhibits a reversible capacity of toward 315.7 mAh/g at 0.1C, accompanied by an ICE of 74.37 % and a 60 % capacity retention after 400 cycles at 10C with a broad temperature range from − 50 to 60 ℃. DFT calculations, XAFS, ex-situ XPS, and in-situ XRD are utilized to study the sodium storage mechanism, which clearly demonstrates the reversibly transform from Zn₃(PO₄)₂ to Na₃PO₄ and Zn particles upon charge/discharge process. The sodium-ion full cell with ZPO@C as anode and Na₃V₂(PO₄)₃ (denoted as NVP) as cathode shows an outstanding electrochemical performance with an ultra-wide operating temperature from − 50 to 60 ℃. Therefore, the work can provide a basis for further development of new conversion-type anode materials for SIBs.