From Meso to Macro: Controlling Hierarchical Porosity in Supraparticle Powders.

A drying droplet containing colloidal particles can consolidate into a spherical assembly called a supraparticle. Such supraparticles are inherently porous due to the spaces between the constituent primary particles. Here, the emergent, hierarchical porosity in spray-dried supraparticles is tailored via three distinct strategies acting at different length scales. First, mesopores (<10 nm) are introduced via the primary particles. Second, the interstitial pores are tuned from the meso- (35 nm) to the macro scale (250 nm) by controlling the primary particle size. Third, defined macropores (>100 nm) are introduced via templating polymer particles, which can be selectively removed by calcination. Combining all three strategies creates hierarchical supraparticles with fully tailored pore size distributions. Moreover, another level of the hierarchy is added by fabricating supra-supraparticles, using the supraparticles themselves as building blocks, which provide additional pores with micrometer dimensions. The interconnectivity of the pore networks within all supraparticle types is investigated via detailed textural and tomographic analysis. This work provides a versatile toolbox for designing porous materials with precisely tunable, hierarchical porosity from the meso- (3 nm) to the macroscale (≈10 µm) that can be utilized for applications in catalysis, chromatography, or adsorption.

Influence of cell opening methods on organic solvent removal during pretreatment in lithium-ion battery recycling.

The use and development of lithium-ion batteries (LIBs) are promoting the technological transformation of individual mobility, consumer electronics and electric energy storage. At their end of life, the complex compounds are disposed by different recycling technologies with defined secondary raw material production. The applied depollution temperatures of the process routes influence not only the recycling efficiency but also the process expenditure, design, medium and costs. Different pretreatment strategies in terms of dismantling depth and depollution temperature are existing. Furthermore, manual and mechanical methods for cell opening are distinguished, which together with the depollution leads to a respective organic solvent evaporation. In this contribution to LIB recycling, the influence of different dismantling depths, achieved by manual cell opening, on the thermal depollution of the LIB cells regarding the mass difference originating by organic solvent evaporation are quantified, in order to determine cell and equipment properties for a safe cell opening. As a result, combinations of thermal depollution and manual cell opening are discussed regarding technical and economic feasibility. The process medium and equipment properties for a safe cell opening are determined. Furthermore, recommendations for future industrial LIB waste management are presented.