Rheo-impedance is the joint use of a rheological measurement and an electrical, electrochemical, or dielectric measurement to follow how a soft material or complex fluid reorganizes as it is processed or as it changes state. The two answer different questions about the same sample: rheology reports how the material flows and how stiff or elastic it is, while impedance, conductivity, and dielectric data report how well charge moves through it and what is happening at its interfaces. Because the mechanical and the electrical responses often depend on different parts of the microstructure, and need not change at the same moment, measuring both can separate states that look identical to either method alone. In this review, “rheo-impedance” is used as an organizing term rather than the name of a single standardized technique. The literature is grouped into three configurations—simultaneous, separate-but-linked, and correlation-based—and five material classes: carbon-black and conductive-colloid suspensions, lithium-ion battery slurries, polymer-electrolyte fuel-cell catalyst inks, gelation and stimuli-responsive systems, and drying, curing, and sintering. Four observations recur across these systems: the mechanical and electrical changes may be linked to the same process yet appear at different stages; a stiffer structure does not necessarily carry charge better; the structure present under flow is not always the one retained after processing; and both agreement and disagreement between the two responses can be informative. Throughout, we try to separate what has been shown experimentally from what is still system-dependent interpretation or future prospect. The main open problems are the ambiguity of equivalent-circuit interpretation, the limited transfer of descriptors between the flowing and the finished state, and the absence of standard geometries, frequency windows, and reporting conventions.

The transition from laboratory-scale experiments to industrial-scale production frequently exposes fundamental challenges related to process similarity. In the context of silicon porosification, achieving consistent results during scale-up requires maintaining thermal, kinematic, geometric, and electrochemical (current/potential) similarities. On the example of two stages of upscaling, this work aims to elucidate the principal scaling effects that arise during the electrochemical porosification of silicon and to outline strategies for mitigating them. Through a series of representative examples, the paper highlights how process parameters, reactor geometry, and operating modes influence the resulting pore architecture and uniformity. A novel inline etching tool is presented where the wafers pass over tanks of alternating polarity. This approach has the great benefit that it does not need a backside contact; however, the alternating tank coverage leads to current density fluctuations under potentiostatic operation. A simple COMSOL simulation (Finite Element Method) of the series resistance network of the system is able to explain the fluctuations qualitatively as well as quantitatively. On this basis, design rules for the next-generation inline etching tool are suggested that would reduce the current density fluctuations from about 50 % to less than 10 %.

Sodium-ion batteries (SIBs) are promising next-generation energy-storage systems, yet their low energy density remains a major challenge. An effective strategy to utilizing low-potential anodes is tuning their electrode potentials with respective to an electrolyte potential window. Herein we propose a molecular framework design of electrolyte solvents to rationally tune sodium electrode potential (E_Na). Extending the alkyl chains of phosphate ester solvents upshifted E_Na by up to 0.32 V (tripropyl phosphate vs. trimethyl phosphate) despite similar donor numbers, indicating a dominant steric effect to weaken the Na⁺ solvation. In contrast, cyclic crown ether 15-crown-5 downshifted E_Na by 0.16 V compared to its linear counterpart (tetraglyme) via the formation of a more stable chelate coordination. Furthermore, the magnitude of these steric/structural effects depended strongly on the cation species, leading to large variations in the Na-Li electrode potential difference (ΔE_Na–Li), from 0.53 V in tripropyl phosphate to 0.10 V in 18-crown-6. Machine-learning-based molecular dynamics simulations revealed that the changes in the cation solvation structure, induced by the solvent molecular framework engineering, are responsible for the observed potential shifts. These findings establish solvent molecular framework engineering as a versatile strategy to tune electrode potentials in battery electrolytes.

Electrochemical conversion of CO₂ into calcium carbide in molten salts has emerged as a promising route for carbon capture and utilization, enabling the production of acetylene, an important industrial chemical. However, continuous operation requires a stable oxygen evolution reaction (OER) at the anode while suppressing competing oxidation of carbonate and carbide species that regenerate CO₂. The anodic reaction mechanism in carbide-containing molten salts remains poorly understood. Here, the anodic behavior and durability of the perovskite oxide La_0.7Sr_0.3FeO_3−δ are investigated in molten NaCl–CaCl₂ at 873 K under controlled anionic environments containing O²⁻, CO₃²⁻, and C₂²⁻. Thermodynamic analysis using potential–pO²⁻ diagrams predicts that carbide oxidation occurs at the most negative potential, followed by carbon, oxide, and carbonate oxidation, which agrees with electrochemical measurements and gas analysis. When O²⁻ and CO₃²⁻ coexist, selective oxygen evolution is achieved with a Faradaic efficiency of 81.4 % and a low corrosion rate of 1.94 × 10⁻⁵ g cm⁻² h⁻¹. In contrast, dissolved C₂²⁻ undergoes anodic oxidation at lower potentials, producing amorphous carbon that accelerates electrode degradation and reduces OER efficiency. These results demonstrate that anodic stability is governed by the local anionic environment, highlighting the importance of maintaining O²⁻ and CO₃²⁻ coexistence while suppressing carbide transport to the anode.

Suppressing zincate crossover is necessary for rechargeable alkaline Zn-MnO₂ rechargeable batteries using electrolytic manganese dioxide (EMD). We benchmarked six commercial separators for their ability to block zincate ions while maintaining the transport of hydroxide ions. Among the separators, FAAM-75-PK (FP75), a commercial anion-exchange membrane, exhibited moderate conductivity (5.8 mS cm⁻¹) with the lowest diffusion coefficient of zincate ions (D_Zn = 2.0 × 10⁻⁸ cm² s⁻¹) and a moderate diffusion coefficient of hydroxide ions (D_OH = 3.5 × 10⁻⁵ cm² s⁻¹), leading to the highest permselectivity (D_OH/D_Zn = 1.7 × 10³). In the galvanostatic discharge–charge tests, FP75 exhibited the best capacity retention of 68 % at the 7th cycle. Characterization of the discharged EMD electrodes revealed that FP75 effectively suppressed ZnMn₂O₄ formation at the cathode, favoring Mn₃O₄ formation instead. The low Zn concentration of 6 ppm in the catholyte is consistent with the favored Mn₃O₄ formation. Beaker-cell tests identify a system-dependent zinc concentration threshold. When the Zn/Mn molar ratio exceeds ∼0.05–0.15, product formation shifts toward ZnMn₂O₄ from Mn₃O₄, and thus, the capacity decay accelerates.