Stable Li-Ion Battery Anode Via in-Situ Reduction of Tin Oxide during Carbonization

A cost-effective method to create a stable Li-ion battery anodes was developed using 1-D Sn/C composite nanofibers via in-situ reduction applied during carbonization process.  The Sn/C nanofibers with tin nanoparticles enclosed within the one-dimensional matrix of carbon backbone were fabricated via water-based electrospinning of tin precursor and water-soluble PVA solution. The manufactured nanofibers were further processed with thermal treatment that incorporates in-situ reduction at 400 C and carbonization at 900 C. The battery anodes utilizing Sn/C nanofibers as the active material exhibited a high capacity and stability due to the robust nature of 1-dimensional carbon backbone that suppresses volume expansion and pulverization of tin nanoparticles. In order to ensure the optimal surface-to-volume ratio of Sn nanoparticles embedded within the carbon backbone, a simple thermal treatment in the air was utilized. For further improvement on battery performance, the same technique and procedure was applied for synthesis of tin-based intermetallic SnM/C nanofibers with Co and Sb utilized as alloying second metals. The addition of inactive transition metal reinforced rigidity of the anode material by confining Sn nanoparticles in its inactive matrix, resulting in reduction of volume change and pulverization. The half-cell battery performance of Sn/C and SnM/C nanofibers yielded a high initial capacity of 600 mAh/g and retained cycling stability up to 300 cycles.