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Developing highly efficient and cost‐effective electrocatalysts for oxygen reduction reaction (ORR) in aqueous media is crucial for energy conversion systems such as fuel cells or Zn‐air batteries. Electrode materials from spent devices such as lithium‐ion batteries (LiBs) are a serious environmental problem. One of the solutions is their reuse for other electrochemical processes. This work demonstrates the application of solid residues of carbon‐based powders left over from the hydrometallurgical recycling process of LIBs' waste as efficient catalysts for ORR. Microscopic and spectroscopic studies of the residue disclosed their porous structure and various cobalt contents, depending on the recycling procedure. These battery wastes display ORR catalytic activity when deposited at the liquid‐liquid and solid electrode‐electrolyte interfaces. Scanning Electrochemical Microscopy (SECM) tests showed that assembling battery waste at the liquid‐liquid interface boosts the efficiency of H2O2 production by one to two orders of magnitude. The catalytic activity towards 2‐electron ORR strongly depends on waste powder compositions and structures, e.g., porosity, heteroatom presence, level of defects, and graphitization. [ABSTRACT FROM AUTHOR]

The front cover of the journal ChemElectroChem showcases the recycling of spent Li-ion batteries through acid leaching and the use of the resulting solid carbon-based materials as electrocatalysts for generating hydrogen peroxide through oxygen reduction. The article explores the relationship between the structure and composition of the battery waste and its electrocatalytic activity. The research was conducted by a team of authors led by Magdalena Warczak and the cover design was done by Dr. Magdalena Osial. For more information, readers can refer to the Research Article with the DOI: 10.1002/celc.202400248. [Extracted from the article]

Producing thick films of conducting polymers by a low‐cost manufacturing technique would enable new applications. However, removing huge solvent volume from diluted suspension or dispersion (1–3 wt%) in which conducting polymers are typically obtained is a true manufacturing challenge. In this work, a procedure is proposed to quickly remove water from the conducting polymer poly(3,4‐ethylenedioxythiophene:poly(4‐styrene sulfonate) (PEDOT:PSS) suspension. The PEDOT:PSS suspension is first flocculated with 1 m H2SO4 transforming PEDOT nanoparticles (≈50–500 nm) into soft microparticles. A filtration process inspired by pulp dewatering in a paper machine on a wire mesh with apertures dimension between 60 µm and 0.5 mm leads to thick free‐standing films (≈0.5 mm). Wire mesh clogging that hinders dewatering (known as dead‐end filtration) is overcome by adding to the flocculated PEDOT:PSS dispersion carbon fibers that aggregate and form efficient water channels. Moreover, this enables fast formation of thick layers under simple atmospheric pressure filtration, thus making the process truly scalable. Thick freestanding PEDOT films thus obtained are used as electrocatalysts for efficient reduction of oxygen to hydrogen peroxide, a promising green chemical and fuel. The inhomogeneity of the films does not affect their electrochemical function. [ABSTRACT FROM AUTHOR]

Thin films of a new composite of an electroactive fullerene-based (C60-Pd) polymer and HiPCO single-wall carbon nanotubes, which were noncovalently modified by 1-pyrenebutiric acid (pyr-SWCNTs), were electrochemically prepared under multiscan cyclic voltammetry conditions. With respect to blank polymer, superior conductive, capacitive, and viscoelasitic properties of the composite were demonstrated. Composition of pyr-SWCNTs was determined by thermogravimetric analyses, which showed one molecule of 1-pyrenebutiric acid per approximately 20 carbon atoms of SWCNT. Atomic force microscopy imaging revealed that pyr-SWCNTs form tangles of pyr-SWCNTs bundles surrounded by globular clusters of the C60-Pd polymer. Peaks characteristic of both pyr-SWCNTs (radial breathing modes at approximately 200 to 300 cm(-1)) and C60-Pd polymer in the Raman spectra recorded for the composite confirmed the presence of pyr-SWCNTs in the composite film. The mass of the deposited film was in situ measured by piezoelectric microgravimetry with the use of an electrochemical quartz crystal microbalance (EQCM). Then, curves of the current, resonant frequency change, and dynamic resistance change versus the potential in different potential ranges were simultaneously recorded in a blank acetonitrile solution of tetrabutylammonium perchlorate. Specific capacitance, determined at -1.20 V for the composite as 90 F g(-1), was twice as high as that for the polymer. Electrochemical impedance spectroscopy was used to determine impedance parameters of both the C60-Pd polymer and C60-Pd/pyr-SWCNTs composite film. This data analysis indicated increased capacitance and decreased resistance for the new composite film.