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Title: Tailoring the surface properties of LiNi0.4Mn0.4Co0.2O₂ by titanium substitution for improved high voltage cycling performance

The present research aims to provide insights into the behavior of LiNi0.4Mn0.4Co0.2O2 (NMC442) and LiNi0.4Mn0.4Co0.2O₂ (NMC442-Ti02) cathode materials under galvanostatic cycling to high potentials, in the context of previous work which predicted that Ti-substituted variants should deliver higher capacities and exhibit better cycling stability than the unsubstituted compounds. It is found that NMC cathodes containing Ti show equivalent capacity fading but greater specific capacity than those without Ti in the same potential range. When repeatedly charged to the same degree of delithiation, NMC cathodes containing Ti showed better capacity retention. Soft x-ray absorption spectroscopy (XAS) spectra for Mn and Co indicated increased reduction in these elements for NMC cathodes without Ti, indicating that the substitution of Ti for Co acts to suppress the formation of a high impedance rock salt phase at the surface of NMC cathode particles. The results of this study validate the adoption of a facile change to existing NMC chemistries to improve cathode capacity retention under high voltage cycling conditions.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [4] ;  [1] ;  [3]
  1. Univ. of California, Berkeley, CA (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  4. SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
OSTI Identifier:
1214098
Report Number(s):
BNL--108310-2015-JA
Journal ID: ISSN 1463-9076; PPCPFQ; KC0403020
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
Physical Chemistry Chemical Physics. PCCP (Print)
Additional Journal Information:
Journal Name: Physical Chemistry Chemical Physics. PCCP (Print); Journal Volume: 17; Journal Issue: 34; Journal ID: ISSN 1463-9076
Publisher:
Royal Society of Chemistry
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE lithium ion battery; Center for Functional Nanomaterials