State Key Laboratory of Powder Metallurgy and School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083, China.
Dalton Trans. 2018 Jun 5;47(22):7522-7527. doi: 10.1039/c8dt01242c.
On account of its high theoretical capacity, silicon (Si) has been regarded as a promising anode material for Li-ion batteries. Extracting Si content from earth-abundant and low-cost aluminosilicate minerals, rather than from artificial silica (SiO2) precursors, is a more favorable and practical method for the large-scale application of Si anodes. In this work, three-dimensionally interconnected (3D-interconnected) Si frameworks with a branch diameter of ∼15 nm are prepared by the reduction of amorphous SiO2 nanotubes derived from natural halloysite clay. Benefiting from their nanostructure, the as-prepared 3D-interconnected Si frameworks yield high reversible capacities of 2.54 A h g-1 at 0.1 A g-1 after 50 cycles, 1.87 A h g-1 at 0.5 A g-1 after 200 cycles, and 0.97 A h g-1 at 2 A g-1 after a long-term charge-discharge process of 500 cycles, remarkably outperforming the commercial Si material. Further, when the as-prepared Si frameworks and commercial LiCoO2 cathodes are paired in full cells, a high anode capacity of 0.98 A h g-1 is achieved after 100 cycles of rapid charge/discharge at 2 A g-1. This work provides a new strategy for the synthesis of high-capacity Si anodes derived from natural aluminosilicate clay.
由于其理论容量高，硅 (Si) 被认为是锂离子电池有前途的阳极材料。从丰富且廉价的铝硅酸盐矿物中提取 Si 含量，而不是从人工二氧化硅 (SiO2) 前体中提取 Si 含量，对于 Si 阳极的大规模应用是一种更有利和实用的方法。在这项工作中，通过还原源自天然埃洛石粘土的无定形 SiO2 纳米管，制备了具有 15nm 左右分支直径的三维互连（3D-interconnected）Si 框架。得益于其纳米结构，所制备的 3D 互连 Si 框架在 50 次循环后在 0.1Ag-1 时具有 2.54A h g-1 的高可逆容量，在 200 次循环后在 0.5Ag-1 时具有 1.87A h g-1 的可逆容量，在 500 次长期充放电过程中在 2Ag-1 时具有 0.97A h g-1 的可逆容量，显著优于商业 Si 材料。此外，当将制备的 Si 框架和商业 LiCoO2 阴极配对组装成全电池时，在 2Ag-1 的快速充放电 100 次循环后，实现了 0.98A h g-1 的高阳极容量。这项工作为从天然铝硅酸盐粘土合成高容量 Si 阳极提供了一种新策略。
