Pyrochlore-type composite oxide Co2Sb2O7@C: advanced anode material for lithium-ion batteries

The pyrochlore-type material Co 2 Sb 2 O 7 @C was synthesized through high-temperature solid-state reactions. Co 2 Sb 2 O 7 and Co 2 Sb 2 O 7 @C were characterized by PXRD, XPS, SEM, EDS, and BET. At the current density of 200 mA g −1 , the first cycle discharge capacity of Co 2 Sb 2 O 7 @C is 1266 mAh g −1 . After 100 cycles, the specific discharge capacity can still reach 463 mAh g −1 , which is higher than the 76 mAh g −1 of Co 2 Sb 2 O 7 . With the increase in scanning rate, the contribution rate of the Co 2 Sb 2 O 7 @C pseudo-capacitor varies from 69.2 to 92.5%. The electrochemical performance is due to the conversion and alloying reaction of Li 3 Sb, the coating of amorphous carbon, and the contribution of pseudo-capacitance.