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Title: Ab initio study of anisotropic mechanical properties of LiCoO{sub 2} during lithium intercalation and deintercalation process

The mechanical properties of Li{sub x}CoO{sub 2} under various Li concentrations and associated anisotropy have been systematically studied using the first principles method. During the lithium intercalation process, the Young's modulus, bulk modulus, shear modulus, and ultimate strength increase with increasing lithium concentration. Strong anisotropy of mechanical properties between a-axis and c-axis in Li{sub x}CoO{sub 2} is identified at low lithium concentrations, and the anisotropy decreases with increasing lithium concentration. The observed lithium concentration dependence and anisotropy are explained by analyzing the charge transfer using Bader charge analysis, bond order analysis, and bond strength by investigating partial density of states and charge density difference. With the decrease of Li concentration, the charge depletion in the bonding regions increases, indicating a weaker Co-O bond strength. Additionally, the Young's modulus, bulk modulus, shear modulus, and toughness are obtained by simulating ab initio tensile tests. From the simulated stress-strain curves, Li{sub x}CoO{sub 2} shows the highest toughness, which is in contraction with Pugh criterion prediction based on elastic properties only.
Authors:
;  [1]
  1. Department of Mechanical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202 (United States)
Publication Date:
OSTI Identifier:
22493033
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 22; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABUNDANCE; ANISOTROPY; BONDING; CHARGE DENSITY; CLATHRATES; COBALT OXIDES; DENSITY OF STATES; ELASTICITY; LITHIUM; LITHIUM COMPOUNDS; SHEAR; SIMULATION; STRAINS; STRESSES; ULTIMATE STRENGTH