New review highlights electrolyte design strategies to stabilize lithium metal battery interfaces

Lithium metal batteries (LMBs) are widely considered one of the most promising next-generation energy storage technologies because of their exceptionally high theoretical energy density. However, their commercial deployment has been hindered by instability at the interface between lithium metal and the electrolyte — a problem that can trigger lithium dendrite growth, electrolyte degradation, capacity loss, and serious safety risks.

A new review published in ENGINEERING Energy systematically examines how advanced electrolyte engineering strategies can stabilize the lithium metal–electrolyte interface and accelerate the development of safer, higher-energy-density batteries. The article, authored by Xiongwu Dong, Liang Chen, Xufeng Zhou, and Zhaoping Liu, provides a comprehensive overview of recent advances in electrolyte design and proposes future directions for synergistic optimization.

Lithium metal anodes possess an ultra-high theoretical specific capacity of 3860 mAh g⁻¹ and the lowest electrochemical potential among anode materials, making them attractive candidates for batteries with energy densities beyond 500 Wh kg⁻¹. Yet their high chemical reactivity leads to unstable interfacial reactions with liquid electrolytes. These reactions continuously consume active lithium and electrolyte components, while also promoting the formation of fragile solid electrolyte interphases (SEIs) and dangerous lithium dendrites.

To address these challenges, the review categorizes and analyzes four major electrolyte design strategies that have emerged in recent years:

• electrolyte additive strategies,
• weakly solvating electrolytes (WSEs),
• high-concentration and localized high-concentration electrolytes (HCEs/LHCEs),
• and novel molecular design approaches.

According to the authors, each strategy regulates lithium-ion solvation structures and interfacial chemistry in different ways, ultimately influencing SEI composition, lithium-ion transport, and dendrite suppression.

The review highlights how additives such as LiNO₃ and fluoroethylene carbonate (FEC) can promote the formation of inorganic-rich SEIs containing Li₂O, Li₃N, and LiF. These inorganic components play complementary roles in improving ionic conductivity, chemical stability, and mechanical robustness at the interface.

Weakly solvating electrolytes, meanwhile, reduce lithium-ion desolvation barriers and promote anion participation in the solvation sheath, enabling the formation of more stable inorganic-rich SEIs. High-concentration electrolyte systems further enhance this effect by increasing the abundance of contact ion pairs and ion aggregates, which favor the preferential reduction of lithium salts at the interface.

The paper also discusses emerging molecular-level design strategies, including asymmetric lithium salts, hybrid solvents, and minimally coordinating diluents. These approaches aim to tailor electrochemical stability windows and interfacial reaction pathways through rational molecular engineering.

Importantly, the authors emphasize that no single electrolyte strategy can independently solve all interfacial challenges. For example, highly ionically conductive SEIs may accelerate corrosion, while chemically stable LiF-rich interphases can suffer from poor ionic transport. As a result, the review proposes that future progress will likely rely on synergistic electrolyte design that integrates multiple strategies simultaneously.

The article additionally surveys advanced characterization and computational techniques used to study lithium metal interfaces, including cryogenic electron microscopy (Cryo-EM), solid-state nuclear magnetic resonance (ssNMR), titration-differential electrochemical mass spectrometry (T-DEMS), density functional theory (DFT), and molecular dynamics (MD) simulations. These methods provide molecular- and nanoscale insights into SEI formation, lithium transport, and electrolyte decomposition mechanisms.

The authors conclude that future electrolyte research should focus on improving interfacial stability under practical operating conditions, including lean electrolyte usage, high cathode loading, and limited lithium excess — conditions essential for commercial-scale lithium metal batteries.

The review provides a unified framework linking electrolyte chemistry, solvation structures, SEI evolution, and interfacial electrochemical stability, offering guidance for the rational design of next-generation high-energy-density batteries.

Journal: ENGINEERING Energy

Read the full article for free: https://rdcu.be/fhjPy

Cite this article
Dong, X., Chen, L., Zhou, X. et al. Stabilizing the Li metal–electrolyte interface: Electrolyte design strategies and synergistic optimization. ENG. Energy 20, 10633 (2026). https://doi.org/10.1007/s11708-026-1063-3