Abstract
A facile electrostatic self-assembly followed by annealing strategy is presented to fabricate Fe2O3 quantum dots embedded nitrogen-doped 3D porous carbon (Fe2O3 QDs/3DNPC) as anode material for lithium ion battery. The ultra-small Fe2O3 QDs (3 similar to 5 nm) are evenly distributed in the carbon matrix after high-temperature calcination, avoiding the obvious agglomeration that usually occurs at high temperature. At the same time, due to the involvement of Fe2O3 QDs, the structure of carbon materials also changed accordingly, e.g., the interlayer spacing of carbon and disorder degree increased. In this way, lithium ions cannot only rapidly transfer between carbon layers, but also react more rapidly with Fe2O3 nanoparticles. On the other hand, 3DNPC can accommodate the volume expansion of Fe2O3 QDs and effectively prevent Fe2O3 QDs from aggregating during charge and discharge processes. Due to its unique structure, Fe2O3 QDs/3DNPC exhibits a high capacity of 531 mAh g (-1) at 0.2 A g (-1) and ultra-high rate performance of 211 mAh g (-1) even at 20 A g (-1) after 1000 cycles. Moreover, this composite also shows an outstanding cycling performance (almost no capacity fading after cycling 1000 times at current densities of 2 A g (-1) 10 A g (-1)and 20 A g (-1)).