Advanced Energy Materials Processing Laboratory, Center for Energy Convergence Research, Korea Institute of Science and Technology (KIST) , Seoul 130-650, Republic of Korea.
School of Chemical Engineering and Materials Science, Chung-Ang University , Seoul 156-756, Republic of Korea.
ACS Appl Mater Interfaces. 2015 Aug 26;7(33):18483-90. doi: 10.1021/acsami.5b04652. Epub 2015 Aug 12.
Silicon (Si) has attracted tremendous attention as a high-capacity anode material for next generation Li-ion batteries (LIBs); unfortunately, it suffers from poor cyclic stability due to excessive volume expansion and reduced electrical conductivity after repeated cycles. To circumvent these issues, we propose that Si can be complexed with electrically conductive Ti2O3 to significantly enhance the reversible capacity and cyclic stability of Si-based anodes. We prepared a ternary nanocomposite of Si/Ti2O3/reduced graphene oxide (rGO) using mechanical blending and subsequent thermal reduction of the Si, TiO2 nanoparticles, and rGO nanosheets. As a result, the obtained ternary nanocomposite exhibited a specific capacity of 985 mAh/g and a Coulombic efficiency of 98.4% after 100 cycles at a current density of 100 mA/g. Furthermore, these ternary nanocomposite anodes exhibited outstanding rate capability characteristics, even with an increased current density of 10 A/g. This excellent electrochemical performance can be ascribed to the improved electron and ion transport provided by the Ti2O3 phase within the Si domains and the structurally reinforced conductive framework comprised of the rGO nanosheets. Therefore, it is expected that our approach can also be applied to other anode materials to enable large reversible capacity, excellent cyclic stability, and good rate capability for high-performance LIBs.
硅（Si）作为下一代锂离子电池（LIBs）的高容量阳极材料引起了极大的关注；不幸的是，由于在反复循环后体积膨胀过大和导电性降低，它的循环稳定性较差。为了解决这些问题，我们提出 Si 可以与导电 Ti2O3 复合，从而显著提高 Si 基阳极的可逆容量和循环稳定性。我们通过机械混合和随后对 Si、TiO2 纳米颗粒和 rGO 纳米片进行热还原，制备了 Si/Ti2O3/还原氧化石墨烯（rGO）的三元纳米复合材料。结果表明，在 100 mA/g 的电流密度下循环 100 次后，所得到的三元纳米复合材料的比容量为 985 mAh/g，库仑效率为 98.4%。此外，这些三元纳米复合材料阳极具有出色的倍率性能特征，即使电流密度增加到 10 A/g。这种优异的电化学性能可以归因于 Si 域内的 Ti2O3 相提供的改进的电子和离子传输，以及由 rGO 纳米片组成的结构增强的导电框架。因此，预计我们的方法也可以应用于其他阳极材料，以实现高容量、优异的循环稳定性和良好的倍率性能的高性能 LIBs。
