Controllable synthesis of 3D nitrogen-doped carbon networks supported SnxPy nanoparticles as high performance anode for lithium ion batteries

SnxPy nanoparticles were controllably synthesized on 3D nitrogen-doped carbon networks (SnxPy/C) by a freeze drying and low-temperature phosphidation process. Interestingly, the product phase (Sn4P3, SnP0.94) could be varied by the SnCl4 concentrations and the doping of SnP0.94 could significantly enhance the cycling properties of Sn4P3 for lithium ion batteries (LIBs). The obtained SnxPy nanoparticles (5-10 nm) were anchored on the 3D nitrogen-doped carbon networks (N-CN), which protected SnxPy from serious agglomeration and large volume expansion. Meanwhile, the N-CN possessed a highly interconnected 3D network structure and good conductivity, so the transportation of Li+ would be speed up to enhance the electrochemical performance. As the LIBs anode, SnxPy/C displayed the best cycling performance with 2M SnCl4 solution, which remained a high capacity of 718 mAh g(-1) after 120 cycles (100 mA g(-1)). The strategy of synthesis SnxPy/C could be expanded to controllable synthesis of other metal phosphides on 3D nitrogen-doped carbon networks for LIBs, catalysis, hydrogen generation, etc.