Tailoring MoO 2 /Graphene Oxide Nanostructures for Stable, High‐Density Sodium‐Ion Battery Anodes

A preform‐decomposition process is employed to prepare a composite of MoO 2 nanoparticles (≈100 nm) anchored on graphene oxide (MoO 2 /GO) for sodium‐ion battery anodes. The discharge gravimetric (volumetric) capacity of the MoO 2 /GO is 483 mAh g −1 (by active material ≈2318 mAh cm −3 ) at the current density of 100 mA g −1 after 10 cycles. After 100 cycles, the discharge gravimetric (volumetric) capacity was maintained at 345 mAh g −1 (≈1656 mAh cm −3 ) and stabilized. During the first 1000 cycles, the capacity degradation is only 1.9 % for each 100 cycles, and the electrode is still able to deliver 276 mAh g −1 after 1000 cycles. Moreover, the nanostructures are able to withstand high rate cycling, the capacity can be fully recovered after being cycled at a rate as high as 2000 mA g −1 . The promising electrochemical performance can be attributed to the high electronic conductivity of MoO 2 and the connected nanostructures, which facilitate both fast electronic and ionic transport.