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Title: Effects of lithium insertion on thermal conductivity of silicon nanowires

Recently, silicon nanowires (SiNWs) have been applied as high-performance Li battery anodes, since they can overcome the pulverization and mechanical fracture during lithiation. Although thermal stability is one of the most important parameters that determine safety of Li batteries, thermal conductivity of SiNWs with Li insertion remains unclear. In this letter, using molecular dynamics simulations, we study room temperature thermal conductivity of SiNWs with Li insertion. It is found that compared with the pristine SiNW, there is as much as 60% reduction in thermal conductivity with 10% concentration of inserted Li atoms, while under the same impurity concentration the reduction in thermal conductivity of the mass-disordered SiNW is only 30%. With lattice dynamics calculations and normal mode decomposition, it is revealed that the phonon lifetimes in SiNWs decrease greatly due to strong scattering of phonons by vibrational modes of Li atoms, especially for those high frequency phonons. The observed strong phonon scattering phenomenon in Li-inserted SiNWs is similar to the phonon rattling effect. Our study serves as an exploration of thermal properties of SiNWs as Li battery anodes or weakly coupled with impurity atoms.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [2] ;  [4]
  1. Department of Physics, Centre for Advanced 2D Material and Centre for Computational Science and Engineering, National University of Singapore, Singapore, Singapore 117546 (Singapore)
  2. (Singapore)
  3. Institute of High Performance Computing, A*STAR, Singapore, Singapore 138632 (Singapore)
  4. (China)
Publication Date:
OSTI Identifier:
22398982
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; ANODES; ATOMS; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; CONCENTRATION RATIO; DECOMPOSITION; FRACTURES; LIFETIME; LITHIUM; MOLECULAR DYNAMICS METHOD; NANOWIRES; PHASE STABILITY; PHONONS; SCATTERING; SILICON; TEMPERATURE RANGE 0273-0400 K; THERMAL CONDUCTIVITY