Nitrogen-doped Carbon-coated SnxOy (x = 1 and y = 0 and 2) Nanoparticles for Rechargeable Li-Ion Batteries

• N-doped carbon-coating of SnxOy (x = 1 and y = 0 and 2) nanoparticles were derived from polyacrylonitrile and poly(vinylpyrrolidone).
• Optimized N-doped carbon-coated SnO2 (50 wt%) and Sn nanoparticles (64 wt%) exhibited the best reversible capacity of 621 mA h g−1 and 650 mA h g−1 after 50 cycles, respectively.
• Such excellent performance can be attributed to the optimum N-doped carbon content/coating level and metal particle size which can effectively increase the stability of the active materials and improve the cycling performance of lithium-ion batteries.

Polyacrylonitrile was used as a precursor to coat N-doped carbon (NC) on SnxOy (x = 1 and y = 0 and 2) nanoparticles. The effect of NC coating on electrochemical performance of SnxOy anodes was investigated. Fine dispersion of metal nanoparticles coated with carbon was observed from microscopic analysis. Systematic studies were performed to understand the electrochemical behavior as well as Li-ion battery performance of the prepared materials. Noticeable capacity improvements for NC-SnO2 and NC-Sn were achieved over carbon-coated particles reported previously in the literature. Among the investigated materials, 50 wt% NC-SnO2 nanoparticles exhibited the best reversible capacity of 621 mA h g−1 while 60 wt% NC-Sn exhibited the highest capacity of 450 mA h g−1 at 100 mA/g after 50 cycles. Electrochemical studies revealed that the carbon shell can effectively increase the stability of the active materials and improve the cycling performance for lithium-ion batteries. NC-protected Sn nanoparticles were also synthesized using poly(vinylpyrrolidone) as a precursor and this material exhibited a significantly high discharge capacity of 650 mA h g−1 at 100 mA/g after 50 cycles. The studies performed on the Sn-based anodes show the potential of carbon content/coating level and metal particle size for improved Li-ion battery performance.

Correlations between microstructure and electrochemical performance of N-doped carbon-coated SnxOy (x = 1 and y = 0 and 2) anodes with various metal loadings, nitrogen contents, and Sn particle size.Figure optionsDownload as PowerPoint slide