Proline-derived in situ synthesis of nitrogen-doped porous carbon nanosheets with encaged Fe2O3@Fe3C nanoparticles for lithium-ion battery anodes

摘要

The homogeneous incorporation of heteroatoms into two-dimensional C nanostructures,which leads to an increased chemical reactivity and electrical conductivity as well as enhanced synergistic catalysis as a conductive matrix to disperse and encapsulate active nanocatalysts,is highly attractive and quite challenging.In this study,by using the natural and cheap hydrotropic amino acid proline-which has remarkably high solubility in water and a desirable N content of ～12.2 wt.％-as a C precursor pyrolyzed in the presence of a cubic KC1 template,we developed a facile protocol for the large-scale production of N-doped C nanosheets with a hierarchically porous structure in a homogeneous dispersion.With concomitantly encapsulated and evenly spread Fe2O3 nano-particles surrounded by two protective ultrathin layers of inner Fe3C and outer onion-like C,the resulting N-doped graphitic C nanosheet hybrids (Fe2O3@Fe3C-NGCNs) exhibited a very high Li-storage capacity and excellent rate capability with a reliable and prolonged cycle life.A reversible capacity as high as 857 mAh.g-1 at a current density of 100 mA·g-1 was observed even after 100 cycles.The capacity retention at a current density 10 times higher-1,000 mA.g-1-reached 680 mAh.g-1,which is 79％ of that at 100 mA·g-1,indicating that the hybrids are promising as anodes for advanced Li-ion batteries.The results highlight the importance of the heteroatomic dopant modification of the NGCNs host with tailored electronic and crystalline structures for competitive Li-storage features.