Surface Properties‐Performance Relationship of Aluminum Foil as Negative Electrode for Rechargeable Aluminum Batteries

Abstract

Rechargeable aluminum batteries with aluminum metal as a negative electrode have attracted wide attention due to the aluminum abundance, its high theoretical capacity and stability under ambient conditions. Understanding and ultimately screening the impact of the initial surface properties of aluminum negative electrodes on the performance and lifetime of the battery cell are of great significance. The purity, surface finishing and degree of hardness of aluminum metal may strongly impact the device’s performance, but these properties have not been systematically studied so far. Here, we present an investigation of the underestimated but crucial role of the aluminum foil surface properties on its electrochemical behavior in aluminum battery half‐cells. The results show that commercial aluminum foils with the same purity and degree of hardness but with different thicknesses (from 0.025 to 0.1 mm) exhibit different microstructure and surface roughness, which in turn have an impact on the cyclability. Atomic force microscopy studies show that the aluminum foil is corroded after repeated electrochemical cycling, thus leading to cell failure. The sample with 0.075 mm thickness exhibits the best cycling stability.

In Situ Monitoring of the Al(110)‐[EMImCl] : AlCl3 Interface by Reflection Anisotropy Spectroscopy

“…This impacts the nucleation and growth of Al deposits, altering the overall electrochemical behaviour. Dendrite formation during Al electrodeposition depends on factors like surface properties of the aluminum substrate, electrolyte, and cycling conditions, and results from inhomogeneous current distribution, ion concentration variations, and defects [39–41] . Single crystals offer defined nucleation sites, promoting or inhibiting dendrite growth based on their surface orientation.…”

“…Dendrite formation during Al electrodeposition depends on factors like surface properties of the aluminum substrate, electrolyte, and cycling conditions, and results from inhomogeneous current distribution, ion concentration variations, and defects. [39][40][41] Single crystals offer defined nucleation sites, promoting or inhibiting dendrite growth based on their surface orientation. As displayed in Figure S7, dendrites were observed on the SEM images of the crystal C2 taken after the experimental series described in Figure S1 was conducted.…”

Modification of Al Surface via Acidic Treatment and its Impact on Plating and Stripping

“…To the best of our knowledge, the literature lacks detailed electrochemical studies of different sides of the Al foil. Typically, one side is only investigated rather than analyzing its performance differences with the other side [41] . This study presents novel insights into the surface properties changes and highlights how different sides of the Al foil undergo microstructure changes after pretreatment and cycling in [EMIm]Cl/AlCl 3 (1 : 1.5) ILE.…”