Toyota Research Institute of North America, 1555 Woodridge Avenue, Ann Arbor, Michigan 48105, USA.
ACS Appl Mater Interfaces. 2013 Aug 28;5(16):7682-7. doi: 10.1021/am4021846. Epub 2013 Aug 19.
The widespread commercialization of today's plug-in hybrid and all electric vehicles will rely on improved lithium batteries with higher energy density, greater power, and durability.To take advantage of the high density of SnO2 anodes for Li ion batteries, we achieved a smart design of monodispersed SnO2/MSCS composite with very high content of SnO2 by a simple infiltration procedure. The synergistic effects of the unique nanoarchitecture of MSCS and the ultrafine size of SnO2 nanoparticle endowed the composite with superior electrochemical performance. Because of the high density of the composite resulting from its monodispersed submicrometer spherical morphology, an exceptionally high reversible lithium storage capacity (both gravimetric and volumetric), very close to the theoretical capacity (1491 mA h/g), can be achieved with good cyclability (capacity retention of 92.5% after 15 cycles). The SnO2/MSCS composite anode exhibited a high reversible average capacity of about 1200 mAh/g over 30 cycles at a current of 80 mAh/g, which corresponds to about 1440 mAh/cm(3) (practical volumetric capacity). In addition, a Coulombic efficiency close to 100% was achieved, and less than 25% first irreversible capacity loss was observed.
为了利用 SnO2 纳米结构在锂离子电池中的高容量，我们采用了一种简单的渗透工艺，实现了具有高 SnO2 含量的单分散 SnO2/MSCS 复合材料的智能设计。MSCS 的独特纳米结构和 SnO2 纳米颗粒的超细尺寸赋予了复合材料优异的电化学性能。由于复合材料具有单分散的亚微米球形形态，密度很高，因此具有极高的可逆锂存储容量（重量和体积），非常接近理论容量（1491 mA h/g），且具有良好的循环性能（经过 15 次循环后容量保持率为 92.5%）。SnO2/MSCS 复合材料在 80 mA/g 的电流密度下，经过 30 次循环后，其可逆平均容量约为 1200 mAh/g，相当于约 1440 mAh/cm3（实际体积容量）。此外，实现了接近 100%的库仑效率，观察到的首次不可逆容量损失不到 25%。
