Synthesis of N-doped multi-cavity Sn/C composite and utilization to anode in lithium ion batteries

Sn based materials have drawn significant research interests owning to their excellent performances as anodes in lithium ion batteries (LIBs). However, the enormous volume change, together with severe Sn particles aggregation during repeated redox cycles present major obstacles for the commercial application in LIBs. Here a simple and scalable approach is developed to construct the nitrogen-doped multi-cavity Sn/C composite through introduction of the polymeric g-C3N4 material which acts as supporting base to anchor 4–6 nm ultrafine active nanoparticles in mild conditions and further as sacrificial agent to produce voids as well as nitrogen dopant for the carbon shell during high temperature pyrolysis. As a result, the nitrogen-doped multi-cavity Sn/C anode displays high specific capacity of 512 mA h g−1 at 1.0 A g−1, good capacity retention of 82% after 1000 cycles and excellent rate performance when used as anode for LIBs. •g-C3N4 material acts as the sacrificial agent to produce voids at high temperature.•g-C3N4 is utilized as the nitrogen source to dope outlayer carbon shell.•Excellent electrochemical performance is achieved due to the improved conductivity and structural stability.