High-capacity silicon anodes are among the most promising routes to boost the energy density of lithium-ion batteries. Yet their appeal is tempered by a familiar problem: silicon swells dramatically during cycling, stressing the electrode and shortening cycle life. A key protective layer that can help is the solid–electrolyte interphase (SEI). In particular, lithium-fluoride (LiF)-rich SEIs have shown strong durability, acting as a stable barrier that limits further electrolyte breakdown.
But making a LiF-based SEI usually comes with a drawback. Many LiF-forming electrolyte strategies rely on anions moving into the lithium-ion solvation environment. That rearrangement weakens the electrolyte’s ability to transport ions quickly. The result is a built-in compromise: improved interphase formation at the cost of lower ionic conductivity, which can undermine fast charging and performance in cold conditions.
In a new study, Chen, Huang, Zhang and co-workers report a solvent-bridged electrolyte design intended to decouple these conflicting requirements. Their approach starts with LiPF6 as the salt source, dissolved in a cosolvent system built around two distinct roles. One solvent type is a bridging cyclic ether that can “share” coordination between Li+ and PF6−, effectively solvating both species. The second solvent component is a structural linear ether that influences the electrolyte’s liquid-range behavior—helpful for keeping the electrolyte functional under harsh temperatures.
By reducing direct Li+–anion contact, the formulation encourages LiF-rich SEI formation without forcing the anions to fully enter the primary lithium solvation sheath. This balance is the core of the reported performance gains: higher ionic conductivity remains available for rapid ion transport, while the interphase still develops the protective LiF component associated with long cycling stability.
The implications are striking for extreme operating scenarios. The authors demonstrate stable cycling of micrometre-sized silicon anodes under fast charge rates exceeding 4 C, where time-dependent polarization typically accelerates degradation. Even more challenging, the electrolyte supports operation down to −55 °C, a temperature at which many conventional electrolytes suffer from sluggish ion motion or partial freezing.
The study also addresses an additional stressor: lithium plating. Under conditions that promote plating, a robust and well-composed SEI can determine whether deposited lithium becomes a durable component of the electrode or a catalyst for continued failure. The solvent-bridged strategy helps maintain favorable interphase chemistry while preserving transport properties.
Overall, solvent-bridged electrolytes offer a conceptually new way to manage the trade-off between SEI chemistry and conductivity. Rather than treating LiF-rich interphases and high-rate, low-temperature performance as mutually exclusive, the work suggests that solvent architecture can be engineered to satisfy both simultaneously, potentially accelerating the path toward high-energy cells that remain reliable in demanding real-world use.
Subject of Research: Solvent-bridged electrolytes for high-energy lithium-ion batteries
Article Title: Solvent-bridged electrolytes for high-energy Li-ion batteries under extreme conditions
Article References: Chen, Y., Huang, F., Zhang, Q. et al. Solvent-bridged electrolytes for high-energy Li-ion batteries under extreme conditions. Nat. Chem. (2026). https://doi.org/10.1038/s41557-026-02221-7
Image Credits: AI Generated
DOI: https://doi.org/10.1038/s41557-026-02221-7
