Mixing amorphous carbon enhanced electrochemical performances of NiCo2O4 nanoparticles as anode materials for sodium-ion batteries

The NiCo 2 O 4 ternary transition metal oxide (NCO) has been received a great interest as anode material for sodium-ion batteries, recently. Here we show that a composite material composed of NCO nanoparticles (NCO-NPs) and amorphous carbon (NCO/C composite) displayed a superior electrochemical performance over the NCO-NPs. The NCO-NPs delivered a capacity of 172 mAh g −1 at the current density of 50 mA g −1 , and the capacity was reduced to 29 mAh g −1 after 50 cycles. The NCO/C composite showed a capacity of 213 mAh g −1 at 50 mA g −1 ; the capacity was lowered to 119 mAh g −1 after 100 cycles. The capacity of the composite at 100 mA g −1 , 200 mA g −1 and 300 mA g −1 was ca. 123 mAh g −1 , 93 mAh g −1 and 62 mAh g −1 , respectively. This improvement is ascribed to the presence of the activated hard carbon of high electronic conductivity. Our work suggests that the combination of amorphous carbon with the NCO-NPs can serve as anodes for sodium-ion batteries.