Tin nanoparticles impregnated in nitrogen-doped graphene for lithium-ion battery anodes

Tin possesses a high theoretical specific capacity as anode materials for Li-ion batteries, and considerable efforts have been contributed to mitigating the capacity fading along with its huge volume expansion during lithium insertion and extraction processes, mainly through nanostructured material design. Herein, we present Sn nanoparticles encapsulated in nitrogen-doped graphene sheets through heat-treatment of the SnO₂ nanocrystals/nitrogen-doped graphene hybrid. The specific architecture of the as-prepared Sn@N-RGO involves three advantages, including a continuous graphene conducting network, coating Sn surface through Sn-N and Sn-O bonding generated between Sn nanoparticles and graphene, and porous and flexible structure for accommodating the large volume changes of Sn nanoparticles. As an anode material for lithium-ion batteries, the hybrid exhibits a reversible capacity of 481 mA h g^-1 after 100 cycles under 0.1 A g^-1 and a charge capacity as high as 307 mA h g^-1 under 2 A g^-1.