Atmospheric Pressure Process for Coating Particles Using Atomic Layer Deposition

Abstract

Abstract Atomic layer deposition (ALD) is a promising technique for coating micrometer‐ and nanometer‐sized particles. Due to the self‐terminating nature of the ALD half‐reactions, the coating thickness can be controlled to the atomic level by choosing the number of cycles in which the half‐reactions are repeated. This technique is performed in a fluidized bed reactor, under atmospheric pressure. LiMn 2 O 4 particles (primary particles 200 − 500 nm in diameter) are coated with Al 2 O 3 to various thicknesses, ranging from 5 ALD cycles to 28 ALD cycles. The resulting coatings are homogeneous, and the individual particles are coated, rather than the agglomerates as a whole; however there are indications of some build‐up of water ‐mainly in pores‐ that may be related to the use of atmospheric pressure. Quantitative characterization of the coating is difficult due to the powdered substrate.