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[交流] 大牛Gerbrand Ceder最新锂电力作（2015年9月18日）已有3人参与

题目：Li-ion conductivity in Li9S3N

作者：Lincoln J. Miara,*a Naoki Suzuki,b William D. Richards,c Yan Wang,c Jae Chul Kim,c and Gerbrand Ceder,cd
      a Samsung Advanced Institute of Technology – USA, 255 Main St., Suite 702, Cambridge, MA 02142, USA. E-mail: lincoln.m@samsung.com
      b Samsung R&D Institute Japan, Mino Semba Center Bldg. 13F, 2-1-11, Semba Nish, Minoh, Osaka 562-0036, Japan
      c Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA
      d Department of Materials Science & Engineering, UC Berkeley, 210 Hearst Mining Building, Berkeley, CA 94720-1760, USA

摘要：Li9S3N (LSN) is investigated as a new lithium ion conductor and barrier coating between an electrolyte and Li metal anode in all solid state lithium ion batteries. LSN is an intriguing material since it has a 3-dimensional conduction channel, high lithium content, and is expected to be stable against lithium metal. The conductivity of LSN is measured with impedance spectroscopy as 8.3 × 10−7 S cm−1 at room temperature with an activation energy of 0.52 eV. Cyclic voltammetry (CV) scans showed reversible Li plating and striping. First principles calculations of stability, nudged elastic band (NEB) calculations, and ab initio molecular dynamics (AIMD) simulations support these experimental results. Substitution as a means to enhance conductivity is also investigated. First-principles calculations predict that divalent cation substituents displace a lithium from a tetrahedral site along the migration pathway, and reduce the migration energy for the lithium ions in the vicinity of the substituent. A percolating path with low migration energies (～0.3 eV) can be formed throughout the crystal structure at a concentration of Li8.5M0.25S3N (M = Ca2+, Zn2+, or Mg2+), resulting in predicted conductivities as high as σ300 K = 2.3 mS cm−1 at this concentration. However, the enhanced conductivity comes at the expense of relatively large substitution energy. Halide substitution, such as Cl on a S site (Image ID:c5ta05432j-t2.gif in Kröger–Vink notation), has a relatively low energy cost, but only provides a modest improvement in conductivity.

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