Herein we report a novel study on the reaction mechanism of non-aqueous aluminum/graphite cell chemistry employing 1-ethyl-3-methylimidazolium chloride:aluminum trichloride (EMIMCl:AlCl₃) as the electrolyte.

Rechargeable graphite dual‐ion batteries are extremely appealing for grid‐level stationary storage of electricity, thanks to the low‐cost and high‐performance metrics, such as high‐power density, energy efficiency, long cycling life, and good energy density. An in‐depth understanding of the anion intercalation mechanism in graphite is fundamental for the design of highly efficient systems. In this work, a comparison is presented between pyrolytic (PG) and natural (NG) graphite as positive electrode materials in rechargeable aluminum batteries, employing an ionic liquid electrolyte. The two systems are characterized by operando synchrotron energy‐dispersive X‐ray diffraction and time‐resolved computed tomography simultaneously, establishing a powerful characterization methodology, which can also be applied more in general to carbon‐based energy‐related materials. A more in‐depth insight into the AlCl₄⁻/graphite intercalation mechanism is obtained, evidencing a mixed‐staged region in the initial phase and a two‐staged region in the second phase. Moreover, strain analysis suggests a correlation between the irreversibility of the PG electrode and the increase of the inhomogenous strain. Finally, the imaging analysis reveals the influence of graphite morphology in the electrode volume expansion upon cycling.

Herein we report on a detailed investigation of the irreversible capacity in the first cycle of pyrolytic graphite electrodes in aluminum batteries employing 1-ethyl-3-methylimidazolium chloride:aluminum trichloride (EMIMCl:AlCl₃) as electrolyte. The reaction mechanism, involving the intercalation of AlCl₄ ⁻ in graphite, has been fully characterized by correlating the micro/nanostructural modification to the electrochemical performance. To achieve this aim a combination of X-ray diffraction (XRD), small angle X-ray scattering (SAXS) and computed tomography (CT) has been used. The reported results evidence that the irreversibility is caused by a very large decrease in the porosity, which consequently leads to microstructural changes resulting in the trapping of ions in the graphite. A powerful characterization methodology is established, which can also be applied more generally to carbon-based energy-related materials.

In this work, we study the electronic and atomic structural modifications occurring in TiO2 anatase nanoparticles as anode materials in Na-ion batteries upon sodiation and desodiation. The structural investigation is performed over both long and short-range order by combing a comprehensive Extended X-Ray Absorption Fine Structure (EXAFS) characterization with X-Ray Diffraction (XRD). The evolution of the electronic structure upon cycling is qualitatively investigated by X-Ray Absorption Near Edge Structure (XANES) analysis. The goal of this work is to correlate the outstanding electrochemical performance of carbon-coated TiO2 anatase nanoparticles in sodium batteries with the electronic and structural modifications induced during the sodiation and desodiation processes upon cycling. This work also demonstrates for the first time a coherent explanation of the structural changes observed, where an electrochemical induced short-range ordering is revealed upon cycling.