Spray‐Drying and Atomic Layer Deposition: Complementary Tools toward Fully Orthogonal Control of Bulk Composition and Surface Identity of Multifunctional Supraparticles

Abstract

Spray‐drying is a scalable process enabling one to assemble freely chosen nanoparticles into supraparticles. Atomic layer deposition (ALD) allows for controlled thin film deposition of a vast variety of materials including exotic ones that can hardly be synthesized by wet chemical methods. The properties of coated supraparticles are defined not only by the nanoparticle material chosen and the nanostructure adjusted during spray‐drying but also by surface functionalities modified by ALD, if ALD is capable of modifying not only the outer surfaces but also surfaces buried inside the porous supraparticle. Simultaneously, surface accessibility in the porous supraparticles must be ensured to make use of all functionalized surfaces. In this work, iron oxide supraparticles are utilized as a model substrate as their magnetic properties enable the use of advanced magnetic characterization methods. Detailed information about the structural evolution upon individual ALD cycles of aluminium oxide, zinc oxide and titanium dioxide are thereby revealed and confirmed by gas sorption analyses. This demonstrates a powerful and versatile approach to freely designing the functionality of future materials by combination of spray‐drying and ALD.

Carbon Microstructure Dependent Li‐Ion Storage Behaviors in SiOx/C Anodes

“…Spray drying being a cost‐effective and ton‐level strategy, has been widely reported effective in the construction of composites secondary particles. [ 18 ] After matching SiO x with HC, SC, and Gr, the secondary particles were constructed under the binding of sucrose ( Figure a). The final products after carbonization were labeled as HCSP, SCSP, and GrSP, respectively.…”

Recording Temperature with Magnetic Supraparticles

“…It is assumed that this reduction results from vanishing of the interstitial pores between the assembled NCPs within the SP, as similarly observed in a previous study. [ 54 ]…”

“…It is assumed that this reduction results from vanishing of the interstitial pores between the assembled NCPs within the SP, as similarly observed in a previous study. [54] Finally, a proof of concept for the temperature indicator functionality of the presented SPs is provided by comparing their spectral magnetic signature via MPS before and after the temperature event (Figure 2b5). On the logarithmically scaled y-axis, it is observed that the harmonic amplitude as a function of higher harmonics decays faster after temperature exposure (red circles) compared to the reference state (as prepared, blue squares).…”

Multifunctional, Hybrid Materials Design via Spray‐Drying: Much more than Just Drying

“…[ 82,83 ] Furthermore, advanced physical and chemical surface layer deposition methods could also be exploited for post‐synthetic surface modifications. Using atomic layer deposition, porous spray‐dried iron oxide particles, [ 84 ] as well as amorphous drug‐loaded particles, [ 85 ] have recently been successfully surface‐modified with various metal oxide (Al 2 O 3 , ZnO, and TiO 2 ) coatings. In general, post‐synthetic surface functionalization may circumvent spray‐drying‐inherent material limitations (see 2.2.)…”