Lithium metal anodes, with a theoretical capacity of up to 3860 mAh·g⁻¹, are regarded as the cornerstone for developing next-generation high-energy-density batteries. However, several key challenges hinder their practical applications, including dendrite formation, unstable solid electrolyte interphase (SEI), side reactions with electrolytes, and associated safety risks. This review systematically explores the mechanisms of lithium nucleation, growth, and stripping in both liquid and solid-state battery systems, analyzing critical theoretical concepts like heterogeneous nucleation thermodynamics, surface diffusion kinetics, space charge effects, and SEI-induced nucleation, which are crucial for understanding the genesis of dendrite growth. Additionally, the review discusses the electrochemical-mechanical coupling failures that lead to SEI degradation and the formation of dead lithium. For liquid systems, the review proposes strategies to mitigate dendrite formation and SEI instability, which include electrolyte optimization, artificial SEI design, and electrode framework design. In solid-state batteries, the review offers a granular analysis of the interface challenges associated with polymer, sulfide, and halide electrolytes and summarizes different solutions for different solid-state electrolytes. Meanwhile, the review emphasizes the importance of advanced characterization techniques and computational modeling in understanding and regulating the interface between lithium metal and electrolytes. Looking ahead, the review highlights future research directions that emphasize the integration of cross-disciplinary approaches to tackle these interconnected challenges. By addressing these issues, the path will be clear for the rapid commercialization and widespread application of lithium metal batteries, bringing us closer to realizing stable, high-energy-density batteries that can satisfy the escalating demands of modern energy storage applications across various industries.

Lithium metal anodes hold great potential for high-energy-density secondary batteries. However, the uncontrollable lithium dendrite growth causes poor cycling efficiency and severe safety concerns, hindering lithium metal anode from practical application. Electrolyte components play important roles in suppressing lithium dendrite growth and improving the electrochemical performance of long-life lithium metal anode, and it is still challenging to effectively compromise the advantages of the conventional electrolyte (1 mol·L⁻¹ salts) and high-concentration electrolyte (> 3 mol·L⁻¹ salts) for the optimizing electrochemical performance. Herein, we propose and design an interfacial high-concentration electrolyte induced by the nitrogen- and oxygen-doped carbon nanosheets (NO-CNS) for stable Li metal anodes. The NO-CNS with abundant surface negative charges not only creates an interfacial high-concentration of lithium ions near the electrode surface to promote charge-transfer kinetics but also enables a high ionic conductivity in the bulk electrolyte to improve ionic mass-transfer. Benefitting from the interfacial high-concentration electrolyte, the NO-CNS@Ni foam host presents outstanding electrochemical cycling performances over 600 cycles at 1 mA·cm⁻² and an improved cycling lifespan of 1,500 h for symmetric cells.