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Title: First-principles investigation of the electronic and Li-ion diffusion properties of LiFePO{sub 4} by sulfur surface modification

We present a first-principles calculation for the electronic and Li-ion diffusion properties of the LiFePO{sub 4} (010) surface modified by sulfur. The calculated formation energy indicates that the sulfur adsorption on the (010) surface of the LiFePO{sub 4} is energetically favored. Sulfur is found to form Fe-S bond with iron. A much narrower band gap (0.67 eV) of the sulfur surface-modified LiFePO{sub 4} [S-LiFePO{sub 4} (010)] is obtained, indicating the better electronic conductive properties. By the nudged elastic band method, our calculations show that the activation energy of Li ions diffusion along the one-dimensional channel on the surface can be effectively reduced by sulfur surface modification. In addition, the surface diffusion coefficient of S-LiFePO{sub 4} (010) is estimated to be about 10{sup −11} (cm{sup 2}/s) at room temperature, which implies that sulfur modification will give rise to a higher Li ion carrier mobility and enhanced electrochemical performance.
Authors:
 [1] ;  [2] ;  [2] ; ; ;  [3] ;  [2]
  1. Concord University College Fujian Normal University, Fuzhou 350117 (China)
  2. (China)
  3. College of Physics and Energy, Fujian Normal University, Fuzhou 350117 (China)
Publication Date:
OSTI Identifier:
22314599
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACTIVATION ENERGY; ADMINISTRATIVE PROCEDURES; ADSORPTION; CARRIER MOBILITY; DIFFUSION; ELECTROCHEMISTRY; FORMATION HEAT; IRON; LITHIUM IONS; MODIFICATIONS; PERFORMANCE; SULFUR; SURFACES; TEMPERATURE RANGE 0273-0400 K