Christopher Gump, Brandon Castro, Andrew Broerman, Arrelaine Dameron, Forge Nano, Thornton, CO While atomic layer deposition (ALD) has found extensive use in the semiconductor industry, it has been generally regarded as too slow or expensive for powder coating applications, even though the precise and nanoscale films could be incredibly useful across many industries. Even so, the number of research publications on the benefits of ALD onto powders has continued to grow over the last 25 years. Fundamentally, ALD on powders is the same as on flat surfaces like silicon wafers. However, much higher mass transfer rates for precursors and reactions products to and from the substrate surface are required. Substrate handling can also be more challenging.
Much of the powder ALD work has been reported in the lithium-ion battery space, where ALD films have been demonstrated to be an effective way of achieving the higher energy densities and charge/discharge rates necessary to speed the commercial adoption of electric vehicles. For these research findings to benefit industry, processes capable of coating large quantities of high-surface area substrates must be developed. To that end, Forge Nano has designed and built commercial-scale tools capable of coating tons of cathode and anode powders in order to standup a robust supply chain for these applications. This talk will highlight the science and engineering for both our semi-batch rotary tool, capable of coating hundreds of kilograms of material with the hundreds of grams of trimethylaluminum and water precursor required per ALD cycle, and our fully continuous vibrating bed tool, capable of coating tens to hundreds of kilograms of material per hour. Products from these tools have been tested in battery cells and shown to have the same performance improvements seen in materials coated at much smaller scale. Results for ALD coatings on Ti64 additive manufacturing feedstocks will also be shared.