Conformal Surface Coatings to Enable High Volume Expansion Li-Ion Anode Materials

• Published in: Chemphyschem Vol. 11; no. 10; pp. 2124 - 2130
• Main Authors: Riley, Leah A., Cavanagh, Andrew S., George, Steven M., Jung, Yoon Seok, Yan, Yanfa, Lee, Se-Hee, Dillon, Anne C.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 12.07.2010; WILEY‐VCH Verlag; Wiley; ChemPubSoc Europe
• Subjects: Chemistry; Colloidal state and disperse state; electrochemical performance; Electrochemistry; electrodes; Exact sciences and technology; General and physical chemistry; kinetics; Li-ion anode materials; lithium; MATERIALS SCIENCE; nanoparticles; phase transitions; Physical and chemical studies. Granulometry. Electrokinetic phenomena; surface analysis; Binary compound; Surface reaction; Heat treatment; Anode; Nanoparticle; Molybdenum oxide; X ray; Surface analysis; Retention; Phase transitions; Contraction; Electrodes; Chemical reduction; lithium; Additive; Energy; Deposition; Lithium ion; Thin coatings; Stability; Transition element compounds; Binders; Adhesion; Coated material; Lithium battery; Transmission electron microscopy; Electrochemistry; Kinetics; Impedance; Alumina
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.201000158

An alumina surface coating is demonstrated to improve electrochemical performance of MoO3 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. An alumina surface coating improves electrochemical performance of MoO3 nanoparticles as high capacity/high‐volume expansion anodes for Li‐ion batteries. Thin, conformal surface coatings are grown using atomic layer deposition (ALD) on both individual nanoparticles and prefabricated electrodes (see figure).