Nitrogen-doped carbon coated SnO2 nanoparticles embedded in a hierarchical porous carbon framework for high-performance lithium-ion battery anodes

SnO2 is one of the promising anode materials for the next-generation lithium-ion batteries due to its high theoretical capacity. The main challenges of SnO2 include large volume change during cycling, partially reversibility between SnO2 and Sn, and unstable solid-electrolyte interphase. Herein, we demonstrate a novel structure design of SnO2-based anode, in which SnO2 nanoparticles are embedded in a hierarchical porous carbon framework and further coated by the uniform Nitrogen-doped carbon layer. The hierarchical porous carbon framework can provide void space for the SnO2 expansion, while the Nitrogen-doped carbon coating can act as a buffer layer to reduce the amount of irreversible solid-electrolyte interphase. This peculiar structure can also build highly conductive network, and promote the reversible conversion from Sn to SnO2 by preventing the agglomeration of the intermediate Sn product. Therefore, the obtained SnO2@HPC@NC composite exhibits remarkable electrochemical performance with a high specific capacity of 1100 mAh g(-1) after 100 cycles at 0.1 A g(-1) and superior long-term stability over 500 cycles at 1 A g(-1).