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Title: Improving the Cycling Life of Aluminum and Germanium Thin Films for use as Anodic Materials in Li-Ion Batteries.

The cycling of high-capacity electrode materials for lithium-ion batteries results in significant volumetric expansion and contraction, and this leads to mechanical failure of the electrodes. To increase battery performance and reliability, there is a drive towards the use of nanostructured electrode materials and nanoscale surface coatings. As a part of the Visiting Faculty Program (VFP) last summer, we examined the ability of aluminum oxide and gold film surface coatings to improve the mechanical and cycling properties of vapor-deposited aluminum films in lithium-ion batteries. Nanoscale gold coatings resulted in significantly improved cycling behavior for the thinnest aluminum films whereas aluminum oxide coatings did not improve the cycling behavior of the aluminum films. This summer we performed a similar investigation on vapor-deposited germanium, which has an even higher theoretical capacity per unit mass than aluminum. Because the mechanism of lithium-alloying is different for each electrode material, we expected the effects of coating the germanium surface with aluminum oxide or gold to differ significantly from previous observations. Indeed, we found that gold coatings gave only small or negligible improvements in cycling behavior of germanium films, but aluminum oxide (Al2O3) coatings gave significant improvements in cycling over the range of film thicknesses tested.
Authors:
 [1] ;  [2] ;  [2]
  1. Dominican Univ., River Forest, IL (United States)
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
OSTI Identifier:
1171580
Report Number(s):
SAND2014--17662R
537421
DOE Contract Number:
AC04-94AL85000
Resource Type:
Technical Report
Research Org:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE