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

The pyrochlore-type material Co2Sb2O7@C was synthesized through high-temperature solid-state reactions. Co2Sb2O7 and Co2Sb2O7@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 Co2Sb2O7@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 Co2Sb2O7. With the increase in scanning rate, the contribution rate of the Co2Sb2O7@C pseudo-capacitor varies from 69.2 to 92.5%. The electrochemical performance is due to the conversion and alloying reaction of Li3Sb, the coating of amorphous carbon, and the contribution of pseudo-capacitance.