Facile Synthesis of a Tin Oxide-Carbon Composite Lithium-Ion Battery Anode with High Capacity Retention

A tin oxide-carbon composite (SnOx-C) was fabricated as a candidate for use as an anode in lithium-ion batteries through the pyrolysis of a ditin citrate precursor. The simultaneous formation of tin oxide and semigraphitized carbon via a facile, solid-state pyrolysis yielded a composite containing tin oxide nanocrystals surrounded by a framework of flexible, porous carbon. Fabrication of tin oxide nanoparticles encased in semigraphitized carbon, led to the enhanced reversibility of Li2O formation, prevented the aggregation of tin during lithiation and suppressed particle fracturing during cycling. The resulting SnOx-C composite exhibited an exceptional electrochemical performance as an anode material candidate for lithium-ion batteries with an initial capacity of 541 mAh g(-1) and 80.6% capacity retention over 400 cycles at a high current density of 900 mA g(-1) (1C). Lower current density studies [450 mA g(-1) (C/2)] have shown the material to have an initial capacity of 667 mAh g(-1) with 88.7% capacity retention over 400 cycles, whereas a current density of 180 mA g(-1) (C/5) gave a capacity of 710 mAh g(-1) with 88.8% capacity retention over 400 cycles. Through a systematic analysis involving X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, cyclic voltammetry, cross-sectional analysis, and post-mortem analysis, we examine how the architecture and composition of the SnOx-C material leads to a high capacity retention tin oxide-carbon composite anode for lithium-ion batteries.