Carbon/Cr2O3 nanocrystal Composites as an Anode with Improved Lithium Storage Performance

Carbon-coated Cr2O3 composites were prepared by the hydrothermal reaction of ammonium chromate ((NH4)2CrO4) and sucrose to form a polymer that was then annealed and carbonized at 600°C under an argon atmosphere to generate nanoparticles of the anodic nanocomposites. The results of electrochemical test showed that the nanocomposite with 49.0 wt% carbon content has more stable and excellent electrochemical performance as the anode material for lithium-ion batteries.. The diameters of the Cr2O3 crystals in the nanocomposites were 20-50 nm, which helped to modulate the volume expansion of Cr2O3 crystals beneath the external carbon shell and ultimately greatly improved the lithium storage performance and discharge/charge (i.e. lithiation/delithiation) cycling stability of the nanocomposites. The specific capacity of the nanocomposite with carbon content of 49.0 wt% was 542 mAh·g-1 after 300 cycles, which was significantly higher than the capacity of the bare Cr2O3 crystals. In addition, as the cycle number increased, the specific capacity of the battery also steadily increased. These results indicated that the composite material is a promising candidate as an anode material for lithium-ion batteries.