Spectroscopic Analysis of Lithium-Ion Battery Interfaces

Spectroscopic analysis of lithium-ion battery interfaces has emerged as a cornerstone for understanding the dynamic formation, evolution and functionality of interphases that govern performance and longevity. At the heart of these studies lies the solid electrolyte interphase (SEI), a nanometre-scale layer formed during initial charge–discharge cycles that passivates the electrode and modulates ion transport. A suite of in situ and operando spectroscopic tools—ranging from vibrational and infrared spectroscopies to X-ray absorption and advanced electron microscopy—enables direct observation of interfacial chemical reactions, morphological changes and layer growth under realistic operating conditions. These insights inform the design of tailored electrolytes, additives and electrode materials, guiding strategies to suppress degradation, enhance cyclability and unlock next-generation chemistries such as silicon-based and solid-state cells. By combining depth sensitivity, high spatial resolution and time-resolved detection, modern spectroscopic methods reveal how interfacial heterogeneities, additive decomposition and electrolyte chemistry interplay to define global battery performance and safety.

Research from Nature Portfolio

Depth-sensitive plasmon-enhanced Raman spectroscopy has been developed to probe the sequential formation and chemical evolution of the SEI on both current collectors and freshly deposited lithium. By exploiting synergistic plasmonic enhancements, this technique uncovers how inorganic and organic SEI components assemble at distinct depths and how lithium deposition alters interphase chemistry to control desolvation and plating behaviour. Operando soft X-ray absorption spectroscopy in total electron yield mode offers nanometre interface sensitivity to map the potential-dependent emergence of LiF and organic carbonyl species on high-capacity silicon anodes. Sequential layering of inorganic and organic SEI constituents and the influence of fluoroethylene carbonate on healing defects have been directly observed. Multiscale in situ infrared nanospectroscopy, integrating optical, atomic force and near-field infrared methods, reveals nanoscale structural and chemical heterogeneities at graphene–solid polymer electrolyte interfaces during lithium plating and stripping. These studies collectively demonstrate the power of combining complementary spectroscopies to resolve buried interphases in their native electrochemical environment.

Spectroscopic Analysis of Lithium-Ion Battery Interfaces publication trend

The graph below shows the total number of articles in spectroscopic analysis of lithium-ion battery interfaces across all publications each year (not limited to Nature Index journals).

Technical terms

Solid electrolyte interphase (SEI): A nanometre-thick passivating film formed on electrode surfaces during initial cycling that prevents continuous electrolyte decomposition while allowing Li-ion transport.

Operando spectroscopy: Characterisation performed under actual electrochemical operating conditions to monitor real-time chemical and structural changes at interfaces.

Plasmon-enhanced Raman spectroscopy: A technique that uses metallic nanostructures to amplify Raman signals, enabling depth-resolved molecular fingerprinting at buried interfaces.

Soft X-ray absorption spectroscopy: An element-specific method measuring absorption at core-level edges with nanoscale interface sensitivity, revealing valence states and bonding environments.

Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR): An infrared approach where an evanescent wave probes thin interfacial films to identify vibrational modes of organic and inorganic species.

Scanning transmission electron microscopy (STEM): A high-resolution imaging technique that, in an electrochemical liquid cell, allows direct visualisation of nanoscale interphase formation in liquid electrolytes.

Infrared nanospectroscopy: A near-field method combining atomic force microscopy with infrared excitation to map chemical heterogeneities at nanometre resolution.

References

1. Mechanistic Understanding of Additive Reductive Degradation and SEI Formation in High‐Voltage NMC811||SiOx‐Containing Cells via Operando ATR‐FTIR Spectroscopy. Advanced Energy Materials (2023).
2. Resolving nanostructure and chemistry of solid-electrolyte interphase on lithium anodes by depth-sensitive plasmon-enhanced Raman spectroscopy. Nature Communications (2023).
3. Operando Electrochemical Liquid Cell Scanning Transmission Electron Microscopy Investigation of the Growth and Evolution of the Mosaic Solid Electrolyte Interphase for Lithium-Ion Batteries. ACS Nano (2023).
4. In situ infrared nanospectroscopy of the local processes at the Li/polymer electrolyte interface. Nature Communications (2022).
5. Revealing solid electrolyte interphase formation through interface-sensitive Operando X-ray absorption spectroscopy. Nature Communications (2022).
6. Vibrational Spectroscopy Insight into the Electrode|electrolyte Interface/Interphase in Lithium Batteries. Advanced Energy Materials (2022).