Synthesis of carbon coated Bi 2 O 3 nanocomposite anode for sodium-ion batteries

Abstract Bi 2 O 3 is a promising sodium storage material due to its high gravimetric specific capacity. However, Bi 2 O 3 possesses lower electrochemical performance due to its poor electrical conductivity and structural integrity during Na + insertion/extraction process. Here, we prepared a carbon coated Bi 2 O 3 nanocomposite by a redox reaction and a carbon coating process. In this nanocomposite, the carbon layer can avoid the direct contact between Bi 2 O 3 and electrolyte, which inhibits the repeated formation and decomposition of solid electrolyte interface film. Additionally, the carbon layer can enhance the electrical conductivity of Bi 2 O 3 and suppress its aggregation due to its volume change during charge and discharge process. In addition, nano-sized Bi 2 O 3 can reduce the transport distance of Na + and electron. The nanocomposite shows excellent cycling performance and rate capability as anode for sodium-ion batteries. A high capacity of 421 mAh g −1 can be maintained after 100 cycles at 1500 mA g −1 and 392 mAh g −1 can be shown at 3200 mAh g −1 .