Atomic insights into the interfacial structure of AlCl3 electrolyte for aqueous aluminum-ion battery

Abstract Revealing the interfacial electric double-layer structure is important for understanding the side reaction and corrosion issues of aqueous Al-ion batteries. Using the molecular dynamics simulation and experimental measurements, this work investigates the electric double-layer structures of representative AlCl 3 aqueous electrolytes, including concentration distribution, electric potential distributions, differential capacitance profile, etc. Results show that the concentration of Al 3+ ions is significantly improved upon the higher charge density, while Al 3+ ions still well maintain the solvation structure and an inner Helmholtz layer of water molecules is observed, which is highly relevant to the interfacial electric potential distributions. Besides, a V-shaped differential capacitance profile is recognized for the AlCl 3 aqueous electrolyte.