Department of Chemical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, Taiwan 30013, ROC.
ACS Nano. 2012 Nov 27;6(11):9932-42. doi: 10.1021/nn303519g. Epub 2012 Oct 12.
We demonstrate that dodecanethiol monolayer passivation can significantly enhance the anode performance of germanium (Ge) nanowires in lithium-ion batteries. The dodecanethiol-passivated Ge nanowires exhibit an excellent electrochemical performance with a reversible specific capacity of 1130 mAh/g at 0.1 C rate after 100 cycles. The functionalized Ge nanowires show high-rate capability having charge and discharge capacities of ∼555 mAh/g at high rates of 11 C. The functionalized Ge nanowires also performed well at 55 °C, showing their thermal stability at high working temperatures. Moreover, full cells using a LiFePO(4) cathode were assembled and the electrodes still have stable capacity retention. An aluminum pouch type lithium cell was also assembled to provide larger current (∼30 mA) for uses on light-emitting-diodes (LEDs) and audio devices. Investigation of the role of organic monolayer coating showed that the wires formed a robust nanowire/PVDF network through strong C-F bonding so as to maintain structure integrity during the lithiation/delithiation process. Organic monolayer-coated Ge nanowires represent promising Ge-C anodes with controllable low carbon content (ca. 2-3 wt %) for high capacity, high-rate lithium-ion batteries and are readily compatible with the commercial slurry-coating process for cell fabrication.
我们证明了十二硫醇单层钝化可以显著提高锂离子电池中锗（Ge）纳米线的阳极性能。经过 100 次循环后，十二硫醇钝化的 Ge 纳米线在 0.1 C 率下具有 1130 mAh/g 的可逆比容量。功能化的 Ge 纳米线具有高倍率性能，在 11 C 的高倍率下具有约 555 mAh/g 的充电和放电容量。功能化的 Ge 纳米线在 55°C 下也表现良好，显示出它们在高工作温度下的热稳定性。此外，使用 LiFePO4阴极组装了全电池，并且电极仍然具有稳定的容量保持率。还组装了一个铝袋式锂电池，以提供更大的电流（约 30 mA），用于发光二极管（LED）和音频设备。对有机单层涂层作用的研究表明，通过强 C-F 键，这些线形成了一个坚固的纳米线/PVDF 网络，从而在锂化/脱锂过程中保持结构完整性。有机单层涂层的 Ge 纳米线代表了具有可控低碳含量（约 2-3 wt%）的有前途的 Ge-C 阳极，具有高容量、高倍率锂离子电池，并且与商业浆料涂覆工艺兼容，适用于电池制造。
