大牛Yi Cui最新锂电力作（Nano Letters，2015年9月29日）？题目：Surface Coating Constraint Induced Self-Discharging of Silicon Nanoparticles as Anodes for Lithium Ion Batteries 作者：Langli Luo1,#, Peng Zhao2,#, Hui Yang2, Borui Liu3, Ji-Guang Zhang4, Yi Cui5,6, GuihuaYu3*, Sulin Zhang2*, and Chong-Min Wang1* ? ?? ?? ?1 Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352, USA ? ?? ?? ?2 Engineering Science and Mechanics and Bioengineering, Pennsylvania State University, University Park, State College, PA 16801, USA ? ?? ?? ?3 Materials Science and Engineering Program and Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA ? ?? ?? ?4 Energy and Environmental Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352, USA ? ?? ?? ?5 Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA ? ?? ?? ?6 Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA ? ?? ?? ?*Correspondence to: E-mail: ghyu@austin.utexas.edu; suz10@psu.edu; Chongmin.Wang@pnnl.gov ? ?? ?? ?#These authors contributed equally to this paper 摘要：One of the key challenges of Si-based anodes for lithium ion batteries is the large volume change upon lithiation and delithiation, which commonly leads to electrochemi-mechanical degradation and subsequent fast capacity fading. Recent studies have shown that applying nanometer-thick coating layers on Si nanoparticle (SiNPs) enhances cyclability and capacity retention. However, it is far from clear how the coating layer function from the point of view of both surface chemistry and electrochemi-mechanical effect. Herein, we use in situ transmission electron microscopy to investigate the lithiation/delithiation kinetics of SiNPs coated with a conductive polymer, polypyrrole (PPy). We discovered that this coating layer can lead to “self-delithiation” or “self-discharging” at different stages of lithiation. We rationalized that the self-discharging is driven by the internal compressive stress generated inside the lithiated SiNPs due to the constraint effect of the coating layer. We also noticed that the critical size of lithiation-induced fracture of SiNPs is increased from ~ 150 nm for bare SiNPs to ~ 380 nm for the PPy-coated SiNPs, showing a mechanically protective role of the coating layer. These observations demonstrate both beneficial and detrimental roles of the surface coatings, shedding light on rational design of surface coatings for silicon to retain high-power and high capacity as anode for lithium ion batteries. 之前相关工作： （1）http://pubs.acs.org/doi/abs/10.1021/nl401880v （2）http://www.nature.com/ncomms/201 ... ssage-global=remove （3）http://pubs.rsc.org/en/content/a ... 40997j#!divAbstract YiCui.png查看更多3个回答 . 20人已关注
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