Ultrasmall Tin Nanodots Embedded in Nitrogen-Doped Mesoporous Carbon: Metal-Organic-Framework Derivation and Electrochemical Application as Highly Stable Anode for Lithium Ion Batteries

•Sn-based metal-organic-framework (MOF) is prepared.•Ultrasmall tin nanodots (2-3 nm) are embedded in nitrogen-doped mesoporous carbon.•The Sn/C composite anode shows high capacity and ultralong cycle life.

This work reports a facile metal-organic-framework based approach to synthesize Sn/C composite, in which ultrasmall Sn nanodots with typical size of 2-3 nm are uniformly embedded in the nitrogen-doped porous carbon matrix (denoted as Sn@NPC). The effect of thermal treatment and nitrogen doping are also explored. Owing to the delicate size control and confined volume change within carbon matrix, the Sn@NPC composite can exhibit reversible capacities of 575 mAh g−1 (Sn contribution: 1091 mAh g−1) after 500 cycles at 0.2 A g−1 and 507 mAh g−1 (Sn contribution: 1077 mAh g−1) after 1500 cycles at 1 A g−1. The excellent long-life electrochemical stability of the Sn@NPC anode has been mainly attributed to the uniform distribution of ultrasmall Sn nanodots and the highly-conductive and flexible N-doped carbon matrix, which can effectively facilitate lithium ion/electron diffusion, buffer the large volume change and improve the structure stability of the electrode during repetitive cycling with lithium ions.

Graphical abstractDownload high-res image (284KB)Download full-size imageThe Sn@NPC composite with ultrasmall Sn nanodots embedded in the nitrogen-doped mesoporous carbon is synthesized by a MOF-based approach and delivers good Li-storage properties.