Monitoring real-world battery degradation is crucial for the widespread application of batteries in different scenarios. However, acquiring quantitative degradation information in operating commercial cells is challenging due to the complex, embedded, and/or qualitative nature of most existing sensing techniques. This process is essentially limited by the type of signals used for detection. Here, we report the use of effective battery thermal conductivity (k_eff) as a quantitative indicator of battery degradation by leveraging the strong dependence of k_eff on battery-structure changes. A measurement scheme based on attachable thermal-wave sensors is developed for non-embedded detection and quantitative assessment. A proof-of-concept study of battery degradation during fast charging demonstrates that the amount of lithium plating and electrolyte consumption associated with the side reactions on the graphite anode and deposited lithium can be quantitatively distinguished using our method. Therefore, this work opens the door to the quantitative evaluation of battery degradation using simple non-embedded thermal-wave sensors.

Composites of metal-organic frameworks and carbon materials have been suggested to be effective materials for the decomposition of chemical warfare agents. In this study, we synthesized UiO-66-NH₂/zeolite-templated carbon (ZTC) composites for the adsorption and decomposition of the nerve agents sarin and soman. UiO-66-NH₂/ZTC composites with good dispersion were prepared via a solvothermal method. Characterization studies showed that the composites had higher specific surface areas than pristine UiO-66-NH₂, with broad pore size distributions centered at 1–2 nm. Owing to their porous nature, the UiO-66-NH₂/ZTC composites could adsorb more water at 80% relative humidity. Among the UiO-66-NH₂/ZTC composites, U_0.8Z_0.2 showed the best degradation performance. Characterization and gas adsorption studies revealed that beta-ZTC in U_0.8Z_0.2 provided additional adsorption and degradation sites for nerve agents. Among the investigated materials, including the pristine materials, U_0.8Z_0.2 also exhibited the best protection performance against the nerve agents. These results demonstrate that U_0.8Z_0.2 has the optimal composition for exploiting the degradation performance of pristine UiO-66-NH₂ and the adsorption performance of pristine beta-ZTC.

Understanding the impact of O₂ during a carbon capture process is vital for designing robust, cost-effective materials for carrying it out. However, mechanistic studies of the O₂-induced degradation of materials are not easily undertaken owing to the complex sequential reaction pathways that arise. Here, we report comprehensive mechanistic investigations of the O₂-induced degradation of diamine-appended metal-organic frameworks (MOFs) exhibiting cooperative CO₂ adsorption. Oxygen exposure experiments were performed on seven different diamine-appended MOFs, including e-2-Mg₂(dobpdc) (e-2 = N-ethylethylenediamine, dobpdc^4- = 4,4'-dioxidobiphenyl-3,3'-dicarboxylate), under various temperatures and O₂ pressures. These experiments show that diamine degradation inhibits CO₂ chemisorption and that the degradation rate is significantly influenced by the diamine structure. In contrast, the parent frameworks remain essentially intact upon O₂ exposure. Detailed characterization of O₂-exposed e-2-Mg₂(dobpdc) revealed the formation of various degradation products, including acetaldehyde, carbon dioxide, water, ethylamine, and other aldehyde- and imine-containing species. Together, these observations suggest that diamine degradation occurs via C-N bond cleavage through pathways involving C-centered radicals. Furthermore, computational evaluation of the initiation and propagation pathways for amine degradation in diamine-appended MOFs indicates that (i) degradation is likely initiated by OH^•, (ii) carbon-centered radicals generated via radical transfer reactions react with O₂, leading to amine degradation, and (iii) the rate-limiting step of the degradation reactions likely involves O-O bond cleavage. Overall, these mechanistic insights could inform strategies for mitigating O₂-induced amine degradation in next-generation carbon capture technologies.