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Conformal Surface Coatings to Enable High Volume Expansion Li‐Ion Anode Materials
Author(s) -
Riley Leah A.,
Cavanagh Andrew S.,
George Steven M.,
Jung Yoon Seok,
Yan Yanfa,
Lee SeHee,
Dillon Anne C.
Publication year - 2010
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201000158
Subject(s) - materials science , conformal coating , electrode , coating , dielectric spectroscopy , anode , atomic layer deposition , chemical engineering , nanoparticle , electrochemistry , layer (electronics) , composite material , nanotechnology , chemistry , engineering
An alumina surface coating is demonstrated to improve electrochemical performance of MoO 3 nanoparticles as high capacity/high‐volume expansion anodes for Li‐ion batteries. Thin, conformal surface coatings were grown using atomic layer deposition (ALD) that relies on self‐limiting surface reactions. ALD coatings were tested on both individual nanoparticles and prefabricated electrodes containing conductive additive and binder. The coated and non‐coated materials were characterized using transmission electron microscopy, energy‐dispersive X‐ray spectroscopy, electrochemical impedance spectroscopy, and galvanostatic charge/discharge cycling. Importantly, increased stability and capacity retention was only observed when the fully fabricated electrode was coated. The alumina layer both improves the adhesion of the entire electrode, during volume expansion/contraction and protects the nanoparticle surfaces. Coating the entire electrode also allows for an important carbothermal reduction process that occurs during electrode pre‐heat treatment. ALD is thus demonstrated as a novel and necessary method that may be employed to coat the tortuous network of a battery electrode.