Construction and electrochemical performance of NaCrO2@Cr2O3 cathode material for sodium-ion batteries

The electrochemical performance of layered O3-type NaCrO 2 cathode material is significantly affected by the side reactions between NaCrO 2 and electrolyte during sodium storage. A uniform Cr 2 O 3 coating layer was in situ constructed on the surface of NaCrO 2 by controlling the excess ratio of sodium source. The structure, morphology, valence and electrochemical performance of the Cr 2 O 3 -coated NaCrO 2 were characterized. The results indicate that the Cr 2 O 3 coating layer does not alter the crystal structure and morphology of NaCrO 2 , but effectively suppresses the side reactions between NaCrO 2 and electrolyte, and improves the surface/interfacial stability of NaCrO 2 material. The Cr 2 O 3 -coated NaCrO 2 exhibits improved electrochemical performance with a capacity retention of 66.4% after 500 cycles at 10 C .