In-situ phase transition to form porous h-MoO3@C nanofibers with high stability for Li+/Na+ storage

Abstract

Porous h-MoO3@C nanofibers with a large specific surface area of 400.2 m2 g−1 were successfully synthesized with hot HNO3 oxidizing MoO2@C nanofibers without obvious damage to carbon shells. As anodes for lithium ion batteries (LIBs), the porous h-MoO3@C nanofibers electrodes show a reversible capacity of 302.9 mA h g−1 at 2 A g−1 after 500 cycles. As anodes for sodium ion batteries (SIBs), they also can deliver a good rate capacity and hold 108.9 mA h g−1 at 2 A g−1 after 500 cycles, even can have 91 mA h g−1 at 5 A g−1 after 1200 cycles. The excellent electrochemical performances of the porous h-MoO3@C nanofibers are attributed to the unique structure which not only can maintain the structure stability but also provide enough active sites for Li+/Na+. At the same time, the tunnel structure of h-MoO3 can lead to separate electron–hole and offer a great deal of special positions for cation (Li+/Na+) insertion/extraction. The present method may be helpful for the synthesis of transition metal oxides (TMOs)-carbon composites with high valence metal atoms in the field of batteries and catalysts.