A reactor for coating particles includes a vacuum chamber configured to hold particles to be coated, a vacuum port to exhaust gas from the vacuum chamber via the outlet of the vacuum chamber, a chemical delivery system configured to flow a process gas into the particles via a gas inlet on the vacuum chamber, one or more vibrational actuators located on a first mounting surface of the vacuum chamber, and a controller configured to cause the one or more vibrational actuators to generate a vibrational motion in the vacuum chamber sufficient to induce a vibrational motion in the particles held within the vacuum chamber.