2, Kansas State University, Manhattan, Kansas, United States
This study reports a high-performance tin (Sn)-coated vertically aligned carbon nanofiber array anode for lithium-ion batteries. The array electrodes has been prepared by coaxially sputter-coating of tin (Sn) shells on vertically aligned carbon nanofiber (VACNF) cores. The robust brush-like highly conductive VACNFs effectively connect high-capacity tin shells for lithium-ion storage. A high specific capacity of 800 mAh g-1 of Sn was obtained at C/5 rate, reaching to the maximum value of amorphous Sn. However, the electrode shows poor cycling performance with conventional LiPF6 based electrolyte. The addition of fluoroethylene carbonate (FEC) improve the performance significantly and Sn-coated VACNFs anode shows stable cycling performance. The Sn-coated VACNF array anodes exhibit outstanding capacity retention in the half-cell tests with electrolyte containing 10% of added FEC and could deliver a reversible capacity of 600 mAh g-1 after 50 cycles at 0.5 C rate.