Search

Advancing electrochemical energy storage devices relies on versatile analytical tools capable of revealing the molecular mechanisms behind the function and degradation of battery materials in situ. The nuclear magnetic resonance phenomenon plays a pivotal role in fundamental studies of energy materials and devices because of its exceptional sensitivity to local environments and the dynamics of many electrochemically relevant elements. The jelly roll architecture is one of the most energy-dense and, therefore, most popular concepts implemented in pouch, prismatic, and cylindrical Li- and Na-ion cells. Such widely commercialized designs, however, represent a significant obstacle for a range of powerful in situmagnetic resonance-based methodologies due to negligible radio frequency electromagnetic field penetration through conductive metal casings and current collectors. In this work, we introduce an experimental setup that enables direct RF wave transmission through the cell terminals and current collectors, and provides efficient excitation and detection of NMR signals. An RF adapter designed as a plug-and-playdevice effectively turns the battery cell into an NMR probe that can be tuned to a broad range of Larmor frequencies. Due to its exceptional sensitivity, versatility, and multinuclear capability, the proposed methodology is suitable for fundamental research and industrial high-throughput screening applications. In situNMR lineshapes provide a direct quantitative description of the chemical environments of electrochemically active elements and enable new metrics for the accurate assessment of state-of-charge (SoC) and state-of-health (SoH). Specifically, in commercial pouch cells based on lithium cobalt oxide, lithium nickel manganese cobalt oxide, and sodium nickel iron manganese oxide chemistries, 7Li and 23Na NMR data unambiguously show electrochemical transformations between intercalated and metallic forms of charge carrier ions, and reveal anisotropic magnetic properties of the electrode coating.

Operando and in situ techniques are becoming mandatory to study Li-ion, post Li-ion, and solid-state batteries. They are essential for monitoring the (electro)chemical and dynamic processes in the battery environment and for providing understanding at different spatial and temporal scales. While operando measurements are becoming more and more routine, scientists have to keep in mind that such experiments are not always harmless for the battery operation, especially when using synchrotron techniques. This is the case in the example described herein with Mg batteries. We show that the electrode reactivity in a InSb/organohaluminate electrolyte/Mg cell is strongly retarded during operando synchrotron X-ray absorption acquisition. Through comparison of ex situ, operando, and in situ data, we demonstrate that this effect occurred only on the samples’ volumes exposed to the X-ray radiation. This study illustrates how incorrect conclusions might be drawn from operando measurements, especially when looking at new battery chemistries, and calls for extreme caution when designing and interpreting operando data.

A In-Pb solid solution is investigated as negative electrode for Mg-ion battery and shows reversible alloying, with upon magnesiation the formation of crystalline Mg2Pb and an electrochemically-driven amorphization of MgIn.

ABSTRACTLead carbonates were used as cosmetic and pigment since Antiquity. The pigment, known as lead white, was generally composed of cerussite and hydrocerussite. Unlike most ancient pigments, lead white was obtained by a synthetic route involving metallic lead, vinegar and organic matter. Fermentation of organic matter produces heat and CO2emission, leading to the formation of carbonates. As lead white is formed by trapping CO2, radiocarbon (14C) dating can thus be considered. We have developed a protocol to prepare lead white. We selected modern pigments for the experiment implementation and ancient cosmetic and paintings for dating. After characterization of the samples by XRD, thermal decomposition of cerussite at various temperatures was explored in order to select the appropriate conditions for painting samples. CO2extraction yield, SEM and XPS were used to characterize the process. Thermal decomposition at 400°C was successfully applied to mixtures of lead white with other paint components (oil as binder, calcite as filler/extender) and to historical samples. We obtained radiocarbon measurements in agreement with the expected dates, demonstrating that thermal decomposition at 400°C is efficient for a selective decomposition of lead white and that paintings can be directly 14C-dated by dating lead white pigment.

Electrochemical behavior and performance of negative electrodes in metal batteries can be modified and improved by combining different elements. Herein, a beneficial coupling of In and Sb in the alloying reaction with Mg was considered through the preparation of the InSb alloy by mechanochemical synthesis. Despite a strong inactivity of Sb as a sole element in Mg-ion batteries, the combination of Sb with In partially unlocks the reversibility of the alloying reaction of Sb with Mg to form Mg3Sb2. For the first time, this beneficial effect is observed not only during the first magnesiation but along few tens of cycles. The analysis of the behavior of InSb through electrochemical and X-ray diffraction measurements also revealed a more complex path than that reported in the literature. Uncommonly, a preferential electrochemically driven amorphization of MgIn is suggested in standard galvanostatic measurements. Crystallization of MgIn is, however, observed through a galvanostatic intermittent titration technique, suggesting strong kinetic effects on the microstructure, strain, or disorder in the InSb phase upon magnesiation.

The radiolysis of nanosized Al(OH)3and AlOOH has been examined. Irradiations were performed using electron beams. H2radiolytic yields were determined with respect to structure and particle size. The measured yields have an order of magnitude of 10–9mol J–1, which decreases when particle size is lowered. Surface and structure analysis techniques were used to detect any change before and after irradiation, and no differences were seen. Annealing experiments showed that a significant amount of molecular hydrogen was trapped inside AlOOH and Al(OH)3. H radicals, F centers, O–and O3–centers were identified by electron paramagnetic resonance (EPR) spectroscopy. A significant part of the absorbed energy remains stored into the nanomaterials and induces a secondary H2production upon heating.