Department of Chemistry, Korea University, Jochiwon 339-700, Korea.
Phys Chem Chem Phys. 2013 Jul 28;15(28):11691-5. doi: 10.1039/c3cp51366a. Epub 2013 Jun 10.
Germanium-tin (Ge(1-x)Sn(x)) alloy nanocrystals were synthesized using a gas-phase laser photolysis reaction of tetramethyl germanium and tetramethyl tin. A composition tuning was achieved using the partial pressure of precursors in a closed reactor. For x < 0.1, cubic phase alloy nanocrystals were exclusively produced without separation of the tetragonal phase Sn metal. In the range of x = 0.1-0.4, unique Ge(1-x)Sn(x)-Sn alloy-metal hetero-junction nanocrystals were synthesized, where the Sn metal domain becomes dominant with x. Thin graphitic carbon layers usually sheathed the nanocrystals. We investigated the composition-dependent electrochemical properties of these nanocrystals as anode materials of lithium ion batteries. Incorporation of Sn (x = 0.05) significantly increased the capacities (1010 mA h g(-1) after 50 cycles) and rate capabilities, which promises excellent electrode materials for the development of high-performance lithium batteries.
采用气相激光光解四甲基锗和四甲基锡的方法合成了锗锡（Ge(1-x)Sn(x)）合金纳米晶体。通过在封闭反应器中控制前体分压实现了组成调谐。对于 x < 0.1，仅生成立方相合金纳米晶体，而没有分离出四方相 Sn 金属。在 x = 0.1-0.4 的范围内，合成了独特的 Ge(1-x)Sn(x)-Sn 合金-金属异质结纳米晶体，其中 Sn 金属畴随着 x 的增加而占据主导地位。薄的石墨碳层通常包覆纳米晶体。我们研究了这些纳米晶体作为锂离子电池阳极材料的组成依赖性电化学性能。掺入 Sn（x = 0.05）显著提高了容量（50 次循环后为 1010 mA h g(-1)）和倍率性能，这为开发高性能锂离子电池提供了优异的电极材料。
