LAUSR

Abstract The synthesis/coating of the negative electrode material Co0.5TiOPO4@C, and its characterization in terms of morphology, crystallographic parameters and electrochemical performance in a sodium half-cell are reported. X-ray diffraction analysis shows that oxyphosphate Co0.5TiOPO4@C crystallize before and after coating at the space group P21/a. The galvanostatic cycling test revealed that Co0.5TiOPO4@C can deliver an initial discharge capacity of 509 mAh/g at C/10 with a large irreversible working plateau at 0.5V. in Operando synchrotron diffraction revealed the mechanism involved upon the first discharge/charge cycle of the Na//Co0.5TiOPO4@C cell at C/5 rate and in the potential window 0.2–3V. The compound undergoes a conversion reaction starting from 0.5V and a complete amorphization is reached at 0.4V.