Center for Nanoparticle Research, Institute for Basic Science (IBS) , Seoul 151-742, Republic of Korea.
Beamline Department, Pohang Accelerator Laboratory (PAL) , Pohang 790-784, Republic of Korea.
J Am Chem Soc. 2015 Sep 23;137(37):11954-61. doi: 10.1021/jacs.5b03673. Epub 2015 Sep 10.
We report a simple synthetic method of carbon-based hybrid cellular nanosheets that exhibit outstanding electrochemical performance for many key aspects of lithium-ion battery electrodes. The nanosheets consist of close-packed cubic cavity cells partitioned by carbon walls, resembling plant leaf tissue. We loaded carbon cellular nanosheets with SnO2 nanoparticles by vapor deposition method and tested the performance of the resulting SnO2-carbon nanosheets as anode materials. The specific capacity is 914 mAh g(-1) on average with a retention of 97.0% during 300 cycles, and the reversible capacity is decreased by only 20% as the current density is increased from 200 to 3000 mA g(-1). In order to explain the excellent electrochemical performance, the hybrid cellular nanosheets were analyzed with cyclic voltammetry, in situ X-ray absorption spectroscopy, and transmission electron microscopy. We found that the high packing density, large interior surface area, and rigid carbon wall network are responsible for the high specific capacity, lithiation/delithiation reversibility, and cycling stability. Furthermore, the nanosheet structure leads to the high rate capability due to fast Li-ion diffusion in the thickness direction.
我们报告了一种简单的基于碳的混合细胞纳米片的合成方法，该方法在锂离子电池电极的许多关键方面表现出优异的电化学性能。这些纳米片由碳壁分隔的紧密堆积的立方腔细胞组成，类似于植物叶片组织。我们通过气相沉积法将 SnO2 纳米颗粒负载在碳细胞纳米片上，并测试了所得 SnO2-碳纳米片作为阳极材料的性能。在 300 次循环中，平均比容量为 914 mAh g(-1)，容量保持率为 97.0%，当电流密度从 200 增加到 3000 mA g(-1)时，可逆容量仅降低了 20%。为了解释优异的电化学性能，我们通过循环伏安法、原位 X 射线吸收光谱和透射电子显微镜对混合细胞纳米片进行了分析。我们发现，高堆积密度、大的内表面面积和刚性的碳壁网络是高比容量、嵌锂/脱锂可逆性和循环稳定性的原因。此外，纳米片结构导致了高倍率性能，因为锂离子在厚度方向上的扩散速度很快。
