Redox-switchable carboranes electrochemically capture and release UO22+ selectively from mixed metal aqueous solutions, mimicking in part spent nuclear fuel.

Utilizing a slurry-based symmetric charge carrier coupled with a conductive carbon additive is a promising method for developing simple, low-cost, and stable hybrid electrochemical flow systems for energy storage. Here, we used a manganese nitride 1,4,8,11,15,18,22,25-octaethoxyphthalocyanine ( EtO PcMnN; 1) as a five-redox-state symmetric charge carrier for slurry-based dual redox flow battery/ capacitor applications. Electrochemical analyses of 1 revealed a wide voltage gap, fast heterogeneous electron-transfer rates, and excellent stability toward galvanostatic cycling. Slurrystate static cell measurements utilizing 1 with a conductive carbon additive, Ketjenblack, were performed and showed high faradaic efficiency and minimal capacity fade using a glass frit porous separator.

Heterogeneous selective capture and release of actinides using redox-switchable carbon electrodes.

The development of inexpensive charge carriers with long-term stability is critical to increase the economic viability of redox flow batteries (RFBs). Herein, we compare the performance metrics of a series of synthesized or commercially available inexpensive phthalocyanine metal (PcM) charge carriers with varying metal-or ligand-based substitution patterns. All systems were charged−discharged as slurries in conjunction with a conductive heterogeneous carbon source, Ketjenblack (KB). The synthesized, peripherally substituted 1,4,8,11,15,18,22,25-octaethoxyphthalocyanine ( EtO Pc) metal complexes, OEt PcVO and OEt PcNi, were cycled with KB, and their performance metrics were compared to their commercially unsubstituted analogues, PcVO and PcNi. No significant advantages were found in using the synthesized versus commercial variants despite the increased solubility of the former. Expanding these electrochemical analyses to several commercial first-row variants (PcTiCl 2 , PcVO, PcMnCl, PcFe, PcCo, PcNi, and PcCu) as well as one heavy-metal analogue (PcPb) revealed that most of these were effective charge carriers for slurry-based PcM/ KB RFB applications. Of these, PcCu proved to have the highest efficiencies, energy density (1.23 Wh/L), and stability (>99% capacity retention) of the series while also having the lowest cost by mass.