New paper published in Cell Press Physical Science on the use of sub-nanometer pores for capacitive deionization to enable membrane-free seawater desalination. Big pores are mighty powerful when it comes to capacitive deionization (CDI). CDI is highly appreciated as a potentially energy-efficient desalination technology, rendering saline water into desalinated (potable/processable) water. However, once we move from saline media with low salt concentrations (like in brackish water regimes) towards higher salt concentrations (as you find in ordinary seawater), CDI become less attractive: the desalination capacity and charge efficiency (think of it as salt removal per invested charge) drop drastically. This issue is linked to the limited permselectivity of carbon pores commonly found in CDI electrodes. Put simply: the invested charge is not only used for adding “extra “ions into the pore (thereby: lowering the feedwater ion concentration) but also to eject ions that are already inside the pore (which basically increases the ion concentration in the effluent stream). We can address this issue by implementing an ion exchange membrane (adding costs and a more complex design) or using charge-transfer materials (giving rise to desalination batteries). But is there a way to keep low-cost, nanoporous carbon and still enable direct, membrane-free seawater desalination? The answer is a resounding YES. In our 2020 paper in Sustainable Energy & Fuels, we showed already the proof of concept of using quasi-ionophobic, and thereby permselective, carbon pores. Now, our work extends the scope and demonstrates this effect’s intricate pore size dependency. The key is a subtle play of pore size and hydrated ion diameter, which allows the pore to only uptake (extra) ions once an electric potential is applied. This work was a great collaboration with the team of Guang Feng at HUST, China, and Christian Prehal at ETH Zürich that puts together simulation and experimental work.

New paper published in ACS Applied Materials & Interfaces. This work in collaboration with the teams of Markus Gallei and Guido Kickelbick (both at Saarland University) explores shear-induced co-assembly as a step towards creating unique (ordered) materials. The latter can be conveniently converted to metal oxide / carbon hybrids via thermal annealing. For example, titanium niobium oxide / carbon obtained this way profided 335 mAh/g at 10 mA/g and a capacity retention of 84% after 1000 cycles at 250 mA/g.

New paper published in the AAAS journal Research on the use of hollow / nanosheet / needle-like cobalt hydroxide for the use for high performance electrochemical desalination. This material architecture allows for rapid ion removal and high stability in absence of strain-build-up. This work was done in collaboration with the team of Jie Ma at Tongji University.

New paper published in ACS Applied Polymer Materials on the use of redox-responsive 2-aminoanthraquinone core-shell particles for structural colors and carbon capture. This work was done in collaboration with the group of Markus Gallei (Saarland University), Karin Jacobs (Saarland University), and T. Alan Hatton (MIT).

New paper published in Sustainable Energy & Fuels on the degradation processes of lithium iron phosphate during electrochemical lithium recovery. Removal of dissolved oxygen suppresses the degradation but also coating of LFP with a thin layer of carbon. This work was done in collaboration with the group of Guido Kickelbick at Saarland University.

New paper published in Cell Reports Physical Science on the use of a conventional fuel cell concept, enhanced by an additional flow channel, for the facile and continuous desalination of seawater. The device consumes oxygen and hydrogen gas and produced electricity, desalted water, and an acid/base couple which conveniently can be used to generate heat.

New paper published in Macromolecular Rapid Communications. Our collaborative with with colleagues from Saarland University (teams of Markus Gallei and Andre Schäfer) and TU Darmstadt shows the synthesis of polyferocenylmethylene and its properties (showcasing reversible electrochemistry).

New paper published in Chemical Engineering Journal on the correlation of ion size / hydrated ion / pore size of sub-1-nm carbon pores. The work was done in collaboration with the team of Guang Feng (HUST, China). The work demonstrates how ion selectivity in mixed ionic systems cannot reliably be predicted by single-salt baseline testing. Also, we demonstrate the importance of durability testing since effects such as ion sieving may very well vary and change over time.

New paper published in Macromolecular Rapid Communications on mechanochromic and pH dependend properties of dye loaded opal structures. This work was done in collaboration with Markus Gallei (Saarland University).

New paper published in Journal of Materials Chemistry A on the use of antimony for water desalination. This may sound, at first, like a contradiction when considering that Sb is not stable in water; yet, the use of a ceramic membrane and an organic electrolyte environment engulfing the antimony electrode allows the stable and high-performance removal of sodium via the antimony – sodium – alloying reaction.