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ACS Appl Mater Interfaces. 2018 Feb 21;10(7):6235-6244. doi: 10.1021/acsami.7b15950. Epub 2018 Feb 8.

Improved Ionic Diffusion through the Mesoporous Carbon Skin on Silicon Nanoparticles Embedded in Carbon for Ultrafast Lithium Storage.

Author information

1
Program of Materials Science & Engineering, Convergence Institute of Biomedical Engineering and Biomaterials and ‡Department of Materials Science and Engineering, Seoul National University of Science and Technology , Seoul 01811, Korea.

Abstract

Because of their combined effects of outstanding mechanical stability, high electrical conductivity, and high theoretical capacity, silicon (Si) nanoparticles embedded in carbon are a promising candidate as electrode material for practical utilization in Li-ion batteries (LIBs) to replace the conventional graphite. However, because of the poor ionic diffusion of electrode materials, the low-grade ultrafast cycling performance at high current densities remains a considerable challenge. In the present study, seeking to improve the ionic diffusion, we propose a novel design of mesoporous carbon skin on the Si nanoparticles embedded in carbon by hydrothermal reaction, poly(methyl methacrylate) coating process, and carbonization. The resultant electrode offers a high specific discharge capacity with excellent cycling stability (1140 mA h g-1 at 100 mA g-1 after 100 cycles), superb high-rate performance (969 mA h g-1 at 2000 mA g-1), and outstanding ultrafast cycling stability (532 mA h g-1 at 2000 mA g-1 after 500 cycles). The battery performances are surpassing the previously reported results for carbon and Si composite-based electrodes on LIBs. Therefore, this novel approach provides multiple benefits in terms of the effective accommodation of large volume expansions of the Si nanoparticles, a shorter Li-ion diffusion pathway, and stable electrochemical conditions from a faster ionic diffusion during cycling.

KEYWORDS:

Li-ion battery; anode; carbon; mesoporous structure; silicon; ultrafast cycling

PMID:
29381857
DOI:
10.1021/acsami.7b15950

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