Room-temperature synthesis of layered open framework cathode for sodium-ion batteries

The synthesis of active electrode materials at room temperature is one of the effective strategies to reduce the fabrication cost of sodium ion batteries(SIBs).Herein,a layered material(Na_(2)[(VO)_(2)(HPO_(4))_(2)C_(2)O_(4)]·2H_(2)O,abbreviated as NVPC followingly)with open-framework structures has been successfully prepared at room temperature under ambient conditions and is evaluated as a cathode for SIBs.It is revealed that NVPC cathode can deliver a maximum reversible capacity of ca.70 mAh/g at 10 mA/g,and exhibit superior rate capability and cycling performance:at 50 mA/g,maximum reversible capacity ca.50 m Ah/g with capacity retention of 88.4%over 250 cycles corresponds to only 0.046%capacity decay per cycle;at 100 mA/g,a maximum reversible capacity of 35 mAh/g with capacity retention of60.9%over 500 cycles.This study demonstrates a practical example of a low-cost synthesis of the cathode materials for SIBs.At the same time,the systematic electrochemical research results also show promising prospects for long lifespan low-cost SIBs.