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.