科研之友
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摘要
In order to further enhance the reversible capacity and cyclability for lithium storage of Sn-based alloy anode materials, a spherical-shaped Sn-Fe3O4@ C ternary-phase composite consisting of nanosized tin (Sn), magnetite (Fe3O4), and graphite (C) was prepared via a two-step process using high-efficiency discharge plasma-assisted milling (P-milling). Ultrafine Sn nanoparticles were embedded and tightly contacted with nanosized Fe3O4, with graphite nanosheets coating the outside to form a multiscale spherical structure. The Sn-Fe3O4@C nanocomposite anodes demonstrate a stable and high capacity of 793 mA h g(-1) after 240 cycles between 0.01 and 3.0 V vs. Li/Li+ at 200 mA g(-1). Furthermore, a reversible capacity of similar to 750 mA h g(-1) was obtained after 500 cycles, even when the current density increased to 2000 mA g(-1). The high capacity, good cycle performance, and superior high-rate capability characteristics were attributed to the unique nanostructure of the Sn-Fe3O4@C composites. The good dispersion of co-existing Sn and Fe3O4 nanoballs in a spherical carbon matrix resulted in an electrode with high structural stability and fast kinetics for Li ion and electron transfer, which contributed to high reversibility of alloying reactions in Sn and conversion reactions of Fe3O4. Furthermore, the spherical shape of the materials and simple preparation as compared to those of commercial anodes make the Sn-Fe3O4@C composites good candidates for practical applications.
- 出版日期2016
- 单位华南理工大学
