Proline-derived in situ synthesis of nitrogen-doped porous carbon nanosheets with encaged Fe203@Fe3C nanoparticles for lithium-ion battery anodes

摘要

The homogeneous incorporation of heteroatoms into two-dimensional Cnanostructures, which leads to an increased chemical reactivity and electricalconductivity as well as enhanced synergistic catalysis as a conductive matrixto disperse and encapsulate active nanocatalysts, is highly attractive and quitechallenging. In this study, by using the natural and cheap hydrotropic aminoacid proline--which has remarkably high solubility in water and a desirable Ncontent of -12.2 wt.%--as a C precursor pyrolyzed in the presence of a cubicKC1 template, we developed a facile protocol for the large-scale production ofN-doped C nanosheets with a hierarchically porous structure in a homogeneousdispersion. With concomitantly encapsulated and evenly spread Fe203 nano-particles surrounded by two protective ultrathin layers of inner Fe3C and outeronion-like C, the resuHing N-doped graphitic C nanosheet hybrids （FezOB@FeBC-NGCNs） exhibited a very high Li-storage capacity and excellent rate capabilitywith a reliable and prolonged cycle life. A reversible capacity as high as 857 mAh.g-1at a current density of 100 mA.g-1 was observed even after 100 cycles. Thecapacity retention at a current density 10 times higher--l,000 mA.g^-l--reached680 mAh·g^-1 which is 79% of that at 100 mA·g^-1, indicating that the hybridsare promising as anodes for advanced Li-ion batteries. The results highlight theimportance of the heteroatomic dopant modification of the NGCNs host withtailored electronic and crystalline structures for competitive Li-storage features.