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 %.

In this study, the lithium morphology plated on Cu substrates and the compositional changes of the solid electrolyte interphase (SEI) film during the first charging process of anode-less batteries (ALBs) were analyzed to clarify their impact on lithium plating/stripping efficiency. In the 1 mol dm⁻³ LiPF₆ in the mixed solvent of ethylene carbonate and dimethyl carbonate (STD), numerous lithium nuclei form in the early stage and subsequently grow into dendritic structures. In contrast, in STD containing tetrakis(trimethylsiloxy)titanium (STD+TMST), nucleation is suppressed and the deposited lithium develops large plate-like morphologies, greatly improving the plating/stripping efficiency. In the STD system, the overall composition of the SEI film formed on both plated lithium and the Cu substrate changes significantly during the first charging process, whereas that of the SEI film formed in STD+TMST remains nearly unchanged. Notably, the SEI films obtained at the fully charged state exhibit almost identical compositions in both electrolytes. These results indicate that the cycling stability of ALBs is determined not only by the final SEI composition but more critically by the compositional changes occurring during the first charging process.

The charge-discharge behaviors of pillared carbon thin-films as an anode of all-solid-state lithium-ion batteries were investigated, using LiBH₄ as the solid electrolyte. The reduced contact area between the pillared carbon thin films and the solid electrolyte resulted in the suppression of side reactions originating from the solid electrolyte. The capacity of the pillared carbon thin-film electrodes increased with the increase in the Si content and reached a very high value of 1278 mAh g⁻¹. Lithium ions were intercalated into the interlayer space of the pillared carbon and the interlayer distance increased from 1.33 to 1.42 nm upon lithium storage. A slight change in the XANES spectrum of the pillared carbon in the Si K-edge region after the introduction of lithium ion indicated that lithium ions were introduced in the vicinity of silicon atom surrounded by 3 oxygen atoms and one methyl group. The present results indicate that pillared carbon is a promising anode material for all-solid-state lithium-ion batteries.

A comparative study was conducted on the electrochemical interaction between CO₂ and various bipyridines, including 2,2′-, 3,3′-, and 4,4′-bipyridine (4,4′-BPy), as well as perfluoro-4,4′-bipyridine (PF-4,4′-BPy). Among these, 4,4′-BPy exhibited the most robust performance, particularly when paired with weakly coordinating quaternary ammonium cations, such as tetrabutylammonium (Bu₄N⁺). The use of these bulky cations proved highly effective in facilitating the electrochemical interaction with CO₂, likely due to their attenuated electrostatic interaction with the bipyridine anionic species, which facilitates reversible CO₂ binding. In contrast, PF-4,4′-BPy exhibited no electrochemical interaction with CO₂; its radical anion showed insufficient nucleophilicity to overcome the activation barrier for CO₂ binding, while the corresponding dianion was highly unstable, leading to rapid decomposition potentially initiated by a reductive defluorination process.

In lithium–oxygen batteries (LOBs), the chemical stability of electrolyte solvents is a critical factor determining cell performance. While sulfonamides represent a promising class of solvents for LOB electrolytes, systematic investigations into the structure–stability relationship of their analogs remain limited. In particular, although reactions involving the α-hydrogen (i.e., hydrogen abstraction and/or deprotonation of the hydrogen atom α to the sulfonyl group) have been widely considered to be initiating steps of solvent decomposition in various electrolytes, their actual impact on solvent decomposition and subsequent battery performance remain unclear. In this study, we performed a comparative analysis to elucidate the structure–stability relationships of sulfonamides with the general structure R¹–SO₂–NCH₃(C₄H₉). Differential electrochemical mass spectrometry (DEMS) measurements revealed that the presence of α-hydrogens is not the dominant factor in solvent decomposition. Instead, the decomposition of the N-alkyl (butyl) chain plays a major role. These results suggest that longer alkyl chains lower the corresponding C–H bond dissociation energies through stabilization of the resulting alkyl radicals, thereby enhancing susceptibility to hydrogen abstraction by reactive oxygen species generated during the discharge/charge process. Our findings indicate that considering only the presence or absence of α-hydrogens is insufficient for designing chemically stable solvents. Rather, minimizing the number of C–H bonds susceptible to hydrogen abstraction is crucial for improving solvent stability.

Mixed-anion compounds are emerging as promising oxygen electrocatalysts; however, the impact of anion-site engineering across various transition metals remains underexplored. Here, we investigate the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) activities of Ruddlesden–Popper-type layered perovskite oxychlorides, Sr₂MeO₃Cl (Me = Mn, Fe, Co, and Ni), and compare them with the corresponding LaSrMeO₄ benchmark oxides. For the OER, chloride substitution universally enhanced the catalytic activity across all investigated transition metals. Density functional theory and X-ray photoelectron spectroscopy revealed that the oxygen p-band center serves as a universal OER activity descriptor, correlating strongly with surface oxygen vacancies and shifting closer to the Fermi level upon chloride incorporation. Conversely, the ORR pathway depends on the transition metal species. While the benchmark oxides predominantly proceed via a two-electron reduction of O₂, Sr₂MnO₃Cl and Sr₂CoO₃Cl oxychlorides exhibit apparent four-electron pathways. Specifically, Sr₂MnO₃Cl drives both direct four-electron and sequential (two-electron reduction followed by peroxide decomposition) pathways, whereas Sr₂CoO₃Cl exclusively utilizes the sequential pathway, facilitated by abundant oxygen vacancies. These findings establish fundamental design principles for tuning bifunctional oxygen electrocatalysis via anion-site engineering.

Ideally ordered anodic porous alumina can be obtained by anodization of an Al substrate with a regular pattern of dimples, which serve as starting points for pore formation. However, because the uniformity of the dimple shapes formed on the Al substrate affects the pore growth behavior, it is essential to form a dimple pattern with a uniform size and shape to prepare ideally ordered anodic porous alumina with a high aspect ratio. In this study, we fabricated ideally ordered anodic porous alumina with an interpore distance of 1.5 µm using dimple patterns formed on an Al surface by two different methods. Based on the 2.5 nm V⁻¹ relationship between interpore distance and voltage in anodic porous alumina, the anodization voltage was set to 600 V. Our study showed that, rather than using an array of dimples formed by mold texturing, using an array of dimples prepared by brief anodization followed by dissolution of the resulting anodic porous alumina yields anodic porous alumina with a uniform pore depth. As a result, it was observed that the uniformity of the pore depth led to improved regularity in the pore arrangement at the bottom of the anodic porous alumina.

The practical application of graphite anodes in sulfide-based all-solid-state lithium-ion batteries is hindered by their poor charging rate capability and interfacial instability caused by the reductive decomposition of solid electrolytes. To address this, we systematically investigated the impact of ultra-thin surface modifications on graphite using atomic layer deposition. Four materials with distinct electronic and lithium-ion conductivities, LiF, Al₂O₃, TiO₂, and Li₃PO₄, were deposited on graphite powder. While all the modifying materials effectively reduced the initial irreversible capacity by suppressing solid electrolyte reduction, TiO₂ and Li₃PO₄ significantly improved the charging rate capability owing to their high lithium-ion conductivities. Furthermore, extended floating tests revealed that the Li₃PO₄ modification uniquely maintained its enhanced rate capability, whereas the TiO₂-modified graphite suffered from kinetic degradation. Because Li₃PO₄ is an electronic insulator, it effectively restricts the continuous reduction of the solid electrolyte compared to TiO₂, which becomes electronically conductive upon lithiation. This study demonstrates that surface modification with a material that is simultaneously an electronic insulator and lithium-ion conductor is crucial for achieving high rate capability and interfacial durability in all-solid-state batteries.

This work demonstrated the electrooxidation of cellulose dissolved in a highly alkaline aqueous solution using Pt nanoparticle electrocatalysts prepared via an ionic liquid/metal sputtering technique. The amount of Pt nanoparticles loaded onto a carbon black support and the quantity of the resulting Pt/C applied to a glassy carbon disk electrode were optimized so as to obtain the highest anodic current. The resulting material outperformed a planar Pt disk electrode and Pt nanoparticles synthesized via a conventional wet chemical reduction method when used to promote cellulose oxidation. This increased performance is attributed to the smaller particle sizes and higher dispersibility of the Pt nanoparticles synthesized through the sputtering method, which combined to increase the electrochemically active surface area.

Electrochemical self-assembly (ESA) by electrolysis in one-pot containing inorganic and organic ingredients results in hybrid materials to exert augmented functionalities due to strong coupling between the constituents in nanoscale. We have recently discovered ESA of redox active hybrid thin films by addition of 2,5-dihydroxy terephthalic acid (DHTPA) to the bath for cathodic electrodeposition of ZnO employing oxygen reduction reaction (ORR). As the process of ESA has been examined, we have unveiled electrocatalysis of ORR by the oxidized form of DHTPA, 2,5-dicarboxy benzoquinone (DCBQ), to promote the growth of ZnO. By contrast, DHTPA is not catalytic for ORR. This “turn-on and -off” of electrocatalysis by redox between DCBQ and DHTPA have nicely explained the peculiar S-shaped I-V curve measured during the electrodeposition by potential cycling (PC method) employing a rotating disk electrode (RDE). The hybrid thin film electrode obtained by the PC method showed fast and stable redox with increased capacities in a neutral Na₂SO₄ solution, superior to those previously achieved by the materials obtained by potentiostatic electrolysis (PS method). Owing to re-construction of hybrid nanostructure during repetitive DHTPA/DCBQ redox, smooth, flat, crack-free and yet highly porous hybrid thin film can be grown thicker by the PC method, while facilitating electronic and ionic transport for the redox reaction. The redox capacity determined in the galvanostatic charging/discharging test at 10C-rate has increased 23 times (6.24 µAh cm⁻²) as compared to that of the PS sample, indicating a large room of further improvements. The process of ESA can therefore be seen as a synthetic route to obtain novel materials for energy storage, out of earth-abundant, non-toxic elements with low process energy, to be combined with extremely safe neutral aqueous electrolyte, ideally suited as ubiquitous power source to back-up wearable electronic devices.