Multifunctional Cr2O3 quantum nanodots to improve the lithium-ion storage performance of free-standing carbon nanofiber networks

Enhanced lithium-ion storage performance of carbon nanofiber networks decorating with uniformly dispersed Cr2O3 quantum nanodots (∼4 nm) totally embedded within them were fabricated via a facile electrospinning method. The composite networks were directly employed as free-standing anode materials for Li ion batteries, which exhibited high specific capacity and stable cyclic performance (527 mAh g−1 in the 100th cycle). The outstanding electrochemical properties of carbon nanofiber networks could be ascribed to the existence of multifunctional Cr2O3 quantum nanodots and the synergistic effect between the Cr2O3 quantum nanodots and carbon. On one hand, Cr2O3 with high theoretical capacity can improve the specific capacity of composites. On the other hand, the embedded Cr2O3 quantum nanodots can effectively promote the defects concentration of carbon nanofibers, resulting in extra lithium-ion storage sites in carbon fiber. In addition, the carbon nanofibers can provide sufficient room to accommodate the huge volume changes of Cr2O3 quantum nanodots during cycling, and also enhance the electronic conductivity and ion diffusion rate as well as granting a good free-standing matrix.