Magnetoelectric (ME) composites offer an alternative route to electromagnetic coupling through the interaction of piezoelectric and magnetostrictive materials, which exhibit electro-mechanical and magneto-mechanical coupling, respectively. A main characteristic of ME devices is operation in a mechanical resonance mode, yielding a Lorentzian type enhancement in α_ME,E, the converse ME coupling coefficient. ME bending mode operation offers exceptionally low spatial size in some frequency ranges, e.g., 6 orders of magnitude in the very low frequency band (3–30 kHz). Most reports dealing with ME bending mode regard only the first mode; furthermore, the available analytical models provide only approximations for on-resonance operation. Here, we present a comprehensive model for ME bending mode operation, offering rigorous, analytical, frequency-dependent expressions for observable quantities such as α_ME,E, impedance, and operation frequency throughout the modal spectrum. We further discuss using higher modes in power transfer, sensing applications, and material property analysis. Overall, the model provides a design and analysis tool for ME device operation.

Exploiting biomass as a fuel source has attracted increasing attention over the last few decades. Combined biotic–abiotic systems can enhance conversion efficiency, but biotic reactions often require oxygen-free conditions, which are hindered by oxygen evolution at the photoanode. Herein, we develop a modular microbial-photoelectrochemical cell (MPEC) that facilitates the one-pot degradation and light-induced conversion of cellulosic material into electrical power and added-value compounds. A BiVO₄ photoanode functionalized with cobalt phosphate (BiVO₄/CoP) was engineered to suppress undesired competing reactions, while enhancing the selectively photooxidation of small organic molecules such as glucose. The anaerobic cellulolytic bacteria, Clostridium thermocellum, convert the insoluble cellulose matter to yield varied saccharides, mainly cellobiose, which are subsequently oxidized by the BiVO₄/CoP photoanode to generate photocurrents. The MPEC demonstrated excellent operational stability for at least three days, maintaining a photocurrent density of ∼400 μA cm⁻². During activation, ethanol (10.7 mM), acetic acid (1.2 mM), and formic acid (2.1 mM) were detected. The performance of the developed MPEC was validated using real-world waste substrates, including Citrus maxima leaves and industrial paper, demonstrating its versatility and robustness. This approach integrates photoelectrochemical energy generation with microbial cellulose degradation, offering a sustainable and practical platform for converting biomass into electrical energy and valuable chemicals.

The robust titanium-based metal–organic framework MIL-125(Ti)-NH₂ was loaded with Cu²⁺ ions (2 %, 5 %) as well as by nanoparticles of Cu⁰ (5 %). The ionic copper species were found to be atomically dispersed within the MOF pores, inducing a slight lattice expansion. In contrast, metallic copper was predominantly deposited at the MOF external surface, resulting in a more significant decrease in BET area. Optical spectroscopy and computational studies revealed that Cu⁰ modification led to a notable narrowing of the bandgap, attributed to the emergence of additional electronic states above the valence band edge, an effect not observed upon incorporation of Cu²⁺ ions. Photoluminescence spectroscopy showed reduced emission intensity upon copper incorporation, with the most pronounced quenching seen in Cu⁰-modified samples. This reduction is associated with both enhanced charge separation and non-radiative deactivation pathways, including phonon-assisted processes, as supported by time-dependent DFT calculations. Nanosecond transient infrared spectroscopy (TRIR) further demonstrated a ligand-to-metal charge transfer from the NH₂-BDC linker to the TiO cluster in pristine MIL-125(Ti)-NH₂, which was extended through localized Ti–O–Cu interactions upon Cu incorporation. The TRIR measurements further indicated an electronic miniband located some 0.2–0.3 eV above Ec for all types of samples. Under visible light, the Cu⁰-loaded MOF outperformed the Cu²⁺-modified analogue in photocatalytic hydrogen evolution. The superior performance of metallic Cu⁰ over ionic Cu²⁺ may originated from reduced rate of radiative recombination as well as from its higher surface energy, which promotes the adsorption of water molecules.

The pyrolysis of biomass is a promising route toward carbon electrodes, but its adoption in electrocatalysis is mostly limited to the oxygen reduction reaction. To prepare precise active sites for other electrocatalytic reactions in the oxygen, nitrogen, and carbon cycles, the complexity of both the biomass precursor and the pyrolysis process must be reigned in. We now report a two-stage strategy for stabilizing the synthesis of a reproducible electrocatalyst for a reaction requiring a precise active site, namely the hydrazine oxidation reaction. The strategy starts with a common yet variable biomass (ground coffee waste) and proceeds through (1) optimized activation by a range of methods, and (2) scalable introduction of Fe–N₄ centers. The result is a sustainable, highly active, and most importantly, reproducible, Fe–N–C electrocatalyst. This work should help the scientific and technological communities to realize the full potential of biomass as a source for carbon electrodes.

Ion exchange membranes are essential components in electrochemical systems, playing a crucial role in energy and environmental applications. These membranes are broadly classified into proton exchange membranes (PEMs) and anion exchange membranes (AEMs). Despite being a relatively young technology, AEMs have attracted considerable attention for energy applications due to their potential to achieve a significant reduction in materials and device costs thanks to their alkaline character. This cost reduction facilitates mass production and commercialization, thereby expanding the applicability of electrochemical energy technologies.

With the rapid growth of renewable energy in the power system and the implementation of high-capacity LCC-HVDC projects, the frequency support capability of the grid is decreasing. Existing centralized single-measurement methods and model-based emergency frequency control (EFC) methods face significant challenges. To fill this gap, this paper proposes a renewables-rich grids EFC method for coordinating LCC-HVDC emergency power support and load shedding. Combined with the system frequency response (SFR) model parameter identification method, the grid frequency regulation capability of different fault conditions is evaluated. A MADRL algorithm with integrated SFR model is developed to overcome the problem of inaccurate assessment of centralized action values in the MADRL algorithm used for EFC, and a decentralized and cooperative EFC strategy is realized. The effectiveness and adaptability of the proposed method is demonstrated by simulating the modified IEEE 39 bus system.

To realize the full potential of waste-derived electrodes, their synthesis must be fully reproducible and their environmental life cycle impact must be assessed quantitatively. We now show how a systematic comparison of coffee wastes as sources for direct hydrazine fuel cell anodes can inform the first full life cycle assessment (LCA) of this application. The result is a practical process yielding active and replicable materials, whose quantified environmental footprint points to actionable avenues for further development.

Electrocatalytic hydrazine oxidation holds great promise for enabling fuel cell-powered transportation since hydrazine hydrate (N₂H₄·H₂O) has the highest energy density of all liquid, CO₂-free fuels (3.45 kWh/L), and the highest fuel cell voltage (1.56 V vs O₂). Inspired by the ruffling of catalytic centers in oxidative enzymes, we designed a twisted single-atom nanozyme comprising twisted FeN₂₊₂C₄₊₄ sites, enabling high accessibility of N₂H₄ and OH^– reactants. Experimental evidence shows that this nanozyme catalyst achieves the lowest oxidation overpotential of all Fe–N–C materials, both in the lab and in direct hydrazine fuel cells, with an open-circuit voltage of 0.95 V, unprecedented for an Fe-based anode. The structure of the catalytic site is elucidated through a combination of electrochemistry, ⁵⁷Fe Mössbauer spectroscopy, high-resolution transmission electron microscopy, and X-ray absorption spectroscopy with crystal field multiplet simulations and fits of the pre-edge features, as well as density functional theory calculations and theoretical simulations of X-ray absorption near edge structure. The experimental and theoretical methods reveal that twisting the active site also shifts its oxidation potential positively and improves N₂ bubble removal while limiting ammonia production to less than 10 ppm. This work demonstrates the potential of active site twisting to enhance the oxidation of energy-rich and liquid substrates, representing a crucial step toward building a sustainable society.

Electrochemical CO₂ reduction catalysis with cobalt corrole complexes in solution is reported. Corroles have attracted attention as contracted and trianionic tetrapyrrolic macrocycles that can be compared to leading porphyrin catalysts for CO₂ reduction, but most studies focus on heterogenized systems with poorly defined electrochemical responses. Electrochemical studies of cobalt corroles bearing axial triphenylphosphine ligands to ensure solubility are reported. The voltammetry provides mechanistic insights supporting CO₂ activation after the formal Co^II/Co^I reduction. The series of cobalt complexes, including a newly designed corrole with mixed perfluorophenyl/ortho-dimethoxyphenyl substituent pattern, provide evidence for electron-rich catalysts having stronger interactions with CO₂. The primary product of CO₂ reduction is CO, formed at a rate of ca. 90 s⁻¹.

Replacing common polymeric binder materials in lithium-ion batteries (LIBs) with more sustainable and environmentally friendly options is one of the challenges in designing new generations of LIBs. Here, we explain how incorporating protein-based polymers into the binder formulation can enhance binder performance in the graphite anode of LIBs. The electrode preparation with these binders involves an atypical thermal treatment (“baking”) that causes structural transformation. The effect of baking temperature on battery performance is examined using various methods covering morphological, structural, and electrochemical aspects. We find that baking the binders at temperatures above 120 °C removes tightly bound water molecules, which impair LIB performance. Water removal promotes intra- and inter-molecular bond formation among the binder components, while the primary covalent structure of these binders remains unchanged. Ultimately, using thermally treated binders enhances the electrochemical performance of graphite anodes and provides strong adhesion. The ideas presented here could significantly influence the design of new binders for LIBs.