Lithium-metal batteries represent a promising next-generation energy storage technology due to their exceptionally high theoretical capacity and low electrochemical potential. However, the commercialization of these batteries has been hindered by the unstable nature of lithium-metal anodes, particularly the formation of dendrites during cycling. Dendrites not only reduce cycling efficiency but also pose significant safety risks by penetrating separators and causing short circuits. To address these challenges, researchers have developed several anode stabilization strategies, including artificial solid-electrolyte interphase layers, electrolyte additives, 3D host structures, and surface coatings. These approaches aim to suppress dendrite growth, improve lithium deposition uniformity, and enhance interfacial stability.

Artificial solid-electrolyte interphase layers have emerged as a critical strategy for stabilizing lithium-metal anodes. The native SEI layer formed during initial cycling is often mechanically weak and chemically unstable, leading to continuous electrolyte decomposition and dendritic growth. Artificial SEI layers are designed to be more robust, with high ionic conductivity and mechanical strength. Materials such as lithium fluoride, lithium nitride, and lithium carbonate have been investigated due to their ability to facilitate uniform lithium-ion flux. Recent studies have demonstrated that nanocomposite artificial SEI layers, combining inorganic and organic components, can provide both flexibility and high modulus, effectively suppressing dendrite penetration. For example, a hybrid layer of lithium fluoride and polymer has shown improved cycling stability over 500 cycles with minimal capacity loss. The challenge lies in achieving scalable fabrication methods that ensure uniform coverage and strong adhesion to the lithium surface.

Electrolyte additives play a significant role in modifying the SEI composition and enhancing anode stability. Additives such as fluoroethylene carbonate, lithium nitrate, and cesium salts have been widely studied for their ability to promote homogeneous lithium deposition. These compounds decompose preferentially during cycling, forming a stable and conductive SEI layer that inhibits dendrite formation. Recent advancements include the use of multi-functional additives that simultaneously improve SEI properties and reduce electrolyte decomposition. For instance, additives containing sulfur or phosphorus have been shown to create a more elastic SEI, accommodating volume changes during cycling. However, the long-term stability of these modified SEI layers under high current densities remains a challenge, as excessive additive concentration can lead to increased interfacial resistance.

3D host structures for lithium-metal anodes offer a physical solution to dendrite suppression by providing a scaffold that guides uniform lithium deposition. These hosts, typically made of conductive and lightweight materials such as carbon, copper, or nickel, distribute current density more evenly and reduce localized plating. Porous carbon matrices, for example, have demonstrated the ability to confine lithium within their structures, preventing uncontrolled growth. Advanced designs incorporate lithiophilic coatings, such as zinc oxide or silicon, to further enhance wetting and nucleation uniformity. A notable development is the use of graphene-based 3D frameworks, which combine high surface area with excellent mechanical properties. Despite these advantages, the increased weight and complexity of 3D hosts can offset some of the energy density benefits of lithium-metal anodes, requiring careful optimization.

Surface coatings on lithium-metal anodes serve as a protective barrier against electrolyte reactions and dendrite formation. Inorganic coatings like aluminum oxide and magnesium oxide have been explored for their ability to block electron transfer while allowing lithium-ion conduction. Polymer coatings, such as polyvinylidene fluoride, provide flexibility and improved interfacial contact. Recent research has focused on hybrid coatings that combine inorganic and organic materials to achieve both mechanical strength and ionic conductivity. For example, a bilayer coating of lithium phosphorus oxynitride and polyacrylonitrile has shown promising results in extending cycle life. The primary limitation of surface coatings is ensuring their durability under repeated stripping and plating cycles, as mechanical degradation can expose fresh lithium to the electrolyte.

Lithium alloying and nanocomposite interfaces represent another avenue for stabilizing lithium-metal anodes. Alloying lithium with elements such as magnesium, aluminum, or silver can reduce its reactivity and improve deposition behavior. These alloys form more stable interfaces with the electrolyte and exhibit lower tendency for dendrite formation. Nanocomposite interfaces, where lithium is combined with nanoparticles of ceramics or polymers, offer enhanced mechanical properties and better ion distribution. Recent work has demonstrated that lithium-silver alloys can achieve stable cycling at high current densities, with over 90% Coulombic efficiency after 200 cycles. The challenge with alloying approaches is maintaining the desired composition during extended cycling, as preferential dissolution of one component can alter the alloy properties over time.

Despite these advancements, several challenges persist in lithium-metal anode stabilization. Uneven lithium deposition remains a critical issue, particularly at high current densities where ion transport limitations become pronounced. Interfacial resistance between the anode and electrolyte also affects battery performance, as excessive resistance leads to voltage polarization and reduced efficiency. Additionally, the dynamic nature of the lithium-electrolyte interface requires continuous adaptation of stabilization strategies to accommodate volume changes and chemical evolution during cycling.

Recent progress in materials science has provided new insights into these challenges. For example, in situ characterization techniques have revealed the nucleation and growth mechanisms of lithium dendrites at nanometer resolution. Computational modeling has also contributed to understanding the relationship between electrolyte composition, SEI properties, and deposition morphology. These tools enable more rational design of stabilization strategies, moving beyond trial-and-error approaches.

In summary, stabilizing lithium-metal anodes requires a multifaceted approach that addresses both chemical and physical aspects of dendrite formation. Artificial SEI layers, electrolyte additives, 3D hosts, and surface coatings each offer unique advantages, but their combination may be necessary for long-term success. Future research should focus on integrating these strategies into scalable manufacturing processes while maintaining the high energy density that makes lithium-metal batteries so attractive. Overcoming the remaining challenges will pave the way for safer and more reliable lithium-metal batteries in applications ranging from electric vehicles to grid storage.