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.

The development of on-demand sterilization systems for highly resistant bacterial spores remains a critical challenge in the fields of food safety and healthcare. In this study, we developed a visible-light-driven photocatalytic system for the in situ generation of organic peroxides from aqueous ethanol solutions using palladium-loaded tungsten trioxide (Pd/WO₃). The loading of Pd nanoparticles (0.1 wt%) significantly enhanced the photocatalytic activity compared to that of bare WO₃, promoting the simultaneous production of hydrogen peroxide (H₂O₂) and organic acids (acetic and formic acids). This enhancement could be attributed to the improved charge carrier separation and the role of Pd in facilitating the reduction of oxygen to H₂O₂. The generated H₂O₂ and organic acids further reacted on the WO₃ surface to form organic peroxides, such as peracetic acid, via a two-step sequential process. Under optimized conditions (80 % v/v EtOH/H₂O), the Pd/WO₃ system achieved a 6-log reduction in Bacillus subtilis spores within 12 h of visible-light irradiation, whereas bare WO₃ required 16 h for the same effect. Our findings demonstrate that the Pd/WO₃ photocatalytic system provides a safe and efficient approach for the localized production of high-level disinfectants, offering a promising alternative to conventional corrosive chemical agents for inactivating resilient pathogens.

The origin of the semi-circles in Nyquist plots of lithium-ion battery composite electrodes obtained using a four-electrode cell was investigated using Li₄Ti₅O₁₂ (LTO) composite electrodes. No distinct semi-circle was observed for the LTO composite electrode, even though the electrolyte within pores was present. In contrast, semi-circles assigned to the impedance related to ionic transport resistance within the composite electrode were observed for the LTO/acetylene black (AB) composite electrode. These results indicate that the presence of the electrolyte within pores is insufficient for the appearance of the semi-circles and that a continuous electronic conduction phase must be formed on the solid side. Thus, the semi-circles are assigned to an apparent R//C response originating from the coupling between ionic transport resistance in the pores and the capacitance made observable by the continuous electronic conduction phase.