期刊
NANO LETTERS
卷 13, 期 10, 页码 4876-4883出版社
AMER CHEMICAL SOC
DOI: 10.1021/nl4027549
关键词
Interface effect; bandgap engineering; lithiation behavior; Ge/Si core/shell nanowire; in situ TEM study
类别
资金
- Laboratory Directed Research and Development (LDRD) program at Los Alamos National Laboratory
- Laboratory Directed Research and Development (LDRD) program at Sandia National Laboratories (SNL)
- Nanostructures for Electrical Energy Storage (NEES), an Energy Frontier Research Center (EFRC)
- U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences [DESC0001160]
- Center for Integrated Nanotechnologies (CINT), a U.S. Department of Energy, Office of Basic Energy Sciences User Facility at Los Alamos National Laboratory [DE-AC52-06NA25396]
- Center for Integrated Nanotechnologies (CINT), a U.S. Department of Energy, Office of Basic Energy Sciences User Facility at Sandia National Laboratories [DE-AC04-94AL85000]
- U.S. Department of Energy's National Nuclear Security Administration [DE-AC04-94AL85000]
Controlling the transport of lithium (Li) ions and their reaction with electrodes is central in the design of Li-ion batteries for achieving high capacity, high rate, and long lifetime. The flexibility in composition; and structure enabled by tailoring electrodes at the nanoscale could drastically change the ionic transport and help meet new levels of Li-ion battery performance. Here, we demonstrate that radial heterostructuring can completely suppress the commonly observed surface insertion of Li ions in all reported nanoscale systems to date and to exclusively induce axial lithiation along the < 111 > direction in a layer-by-layer fashion. The new lithiation behavior is achieved, through the deposition of a conformal, epitaxial, and ultrathin silicon (Si) shell on germanium (Ge) nanowires, which creates an effective chemical potential barrier for Li ion diffusion through and reaction at the nanowire surface, allowing only axial lithiation and volume expansion. These results demonstrate for the first time that interface and bandgap engineering of electrochemical reactions can be utilized to control the nanoscale ionic transport/insertion paths and thus may be a new tool to define the electrochemical reactions in Li ion batteries.
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