The Solid-Electrolyte-Interphase (SEI) model, introduced in 1979 by Peled, revolutionized the understanding of lithium batteries by showing that direct electron transfer from the electrode to lithium ions in solution is incorrect. Instead, the SEI forms a protective layer that prevents such electron transfer, reducing self-discharge and improving battery performance. The SEI model provides equations for electrode kinetics, anode corrosion, SEI resistivity, growth rate, and irreversible capacity loss. It has become a cornerstone in lithium battery science and technology. The SEI is essential for the safe and efficient operation of lithium and sodium batteries. It acts as a solid electrolyte with high electronic resistivity, preventing corrosion and ensuring the battery's longevity. The SEI's properties, such as high electrical resistance, cation selectivity, and mechanical stability, are crucial for battery performance. However, current SEI layers do not yet fully meet these requirements, as they continue to grow during charge-discharge cycles. The SEI forms when an alkali metal is immersed in an electrolyte or when a negative potential is applied to an electrode. The formation involves reduction reactions of salts, solvents, and impurities, leading to the deposition of inorganic compounds like LiF, LiCl, and Li₂O, as well as insoluble SEI components like Li₂CO₃ and semi-carbonates. The SEI's thickness and composition depend on factors such as the type of carbon, temperature, and solvent. The SEI's structure is complex, consisting of multiple layers, with the inner layer being compact and the outer layer being porous. The SEI's properties, such as its resistivity and thickness, are influenced by the electrolyte's composition and the anode's surface. The SEI's formation is critical for battery performance, as it affects the battery's safety, power capability, and cycle life. The SEI's formation and growth are influenced by factors such as the electrolyte's composition, the anode's surface, and the current density. The SEI's properties, such as its resistivity and thickness, are crucial for battery performance, and its formation is a key factor in the battery's longevity and safety. The SEI's structure and composition are studied using various techniques, including XPS, SEM, XRD, and TOF-SIMS. The SEI's properties are also influenced by the electrolyte's composition, with certain anions and solvents being more reactive toward solvated electrons. The SEI's formation is a critical process in lithium batteries, affecting the battery's performance, safety, and longevity. The SEI's properties, such as its resistivity and thickness, are crucial for battery performance, and its formation is a key factor in the battery's longevity and safety. The SEI's structure and composition are studied using various techniques, including XPS, SEM, XRD, and TOThe Solid-Electrolyte-Interphase (SEI) model, introduced in 1979 by Peled, revolutionized the understanding of lithium batteries by showing that direct electron transfer from the electrode to lithium ions in solution is incorrect. Instead, the SEI forms a protective layer that prevents such electron transfer, reducing self-discharge and improving battery performance. The SEI model provides equations for electrode kinetics, anode corrosion, SEI resistivity, growth rate, and irreversible capacity loss. It has become a cornerstone in lithium battery science and technology. The SEI is essential for the safe and efficient operation of lithium and sodium batteries. It acts as a solid electrolyte with high electronic resistivity, preventing corrosion and ensuring the battery's longevity. The SEI's properties, such as high electrical resistance, cation selectivity, and mechanical stability, are crucial for battery performance. However, current SEI layers do not yet fully meet these requirements, as they continue to grow during charge-discharge cycles. The SEI forms when an alkali metal is immersed in an electrolyte or when a negative potential is applied to an electrode. The formation involves reduction reactions of salts, solvents, and impurities, leading to the deposition of inorganic compounds like LiF, LiCl, and Li₂O, as well as insoluble SEI components like Li₂CO₃ and semi-carbonates. The SEI's thickness and composition depend on factors such as the type of carbon, temperature, and solvent. The SEI's structure is complex, consisting of multiple layers, with the inner layer being compact and the outer layer being porous. The SEI's properties, such as its resistivity and thickness, are influenced by the electrolyte's composition and the anode's surface. The SEI's formation is critical for battery performance, as it affects the battery's safety, power capability, and cycle life. The SEI's formation and growth are influenced by factors such as the electrolyte's composition, the anode's surface, and the current density. The SEI's properties, such as its resistivity and thickness, are crucial for battery performance, and its formation is a key factor in the battery's longevity and safety. The SEI's structure and composition are studied using various techniques, including XPS, SEM, XRD, and TOF-SIMS. The SEI's properties are also influenced by the electrolyte's composition, with certain anions and solvents being more reactive toward solvated electrons. The SEI's formation is a critical process in lithium batteries, affecting the battery's performance, safety, and longevity. The SEI's properties, such as its resistivity and thickness, are crucial for battery performance, and its formation is a key factor in the battery's longevity and safety. The SEI's structure and composition are studied using various techniques, including XPS, SEM, XRD, and TO