Electrochemical Interfaces in Lithium-Ion Battery Systems

Electrochemical interfaces in lithium-ion batteries encompass the complex boundary regions where electrodes meet electrolytes, governing charge transfer, ionic transport and interfacial stability. At the negative electrode, the solid–electrolyte interphase (SEI) forms through electrolyte reduction, creating a passivation layer that permits Li⁺ conduction while preventing further solvent breakdown. At the positive electrode, a related cathode–electrolyte interphase (CEI) evolves from oxidative reactions, influencing capacity retention and high-voltage performance. In solid‐state configurations, the contact between rigid electrodes and inorganic or polymer electrolytes requires intimate solid–solid interfaces to minimise resistance and suppress dendrite propagation. Across all systems, interfacial phenomena such as solvent decomposition, mechanical fracture of surface films and localised phase changes dictate cycle life, safety and energy density. Advances in in situ characterisation and modelling have elucidated the spatial distribution of interphase components, the mechanical properties of nascent films and the chemical pathways leading to impedance growth. A detailed understanding of these interfacial processes is essential for the rational design of next-generation batteries with improved durability and performance.

Research from Nature Portfolio

Operando X-ray photoelectron spectroscopy of a Li/Li₂S-P₂S₅ solid-electrolyte system has revealed the stepwise decomposition of the electrolyte into Li₂S and Li₃P, with oxygen impurities yielding Li₃PO₄ and Li₂O. The spatially heterogeneous distribution of these phases was linked to variations in local ionic conductivity and overpotential, underlining the need for uniform interphase design in solid-state batteries. In parallel, in situ gravimetric and viscoelastic measurements on Li₄Ti₅O₁₂ electrodes have quantified the mass uptake and mechanical stiffness of SEI films formed in different electrolyte compositions. These studies identified that additives such as vinylene carbonate markedly increase film rigidity and alter viscoelastic properties, offering pathways to engineer more robust anode passivation. More recently, synchrotron X-ray diffraction combined with mass spectrometry during thermal ramping of lithiated graphite electrodes uncovered SEI decomposition, lithium leaching and H₂ evolution. The findings emphasise the critical role of SEI chemistry in anode thermal stability and highlight safety-critical gas-release mechanisms under abuse conditions.

Electrochemical Interfaces in Lithium-Ion Battery Systems publication trend

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

Technical terms

Solid–electrolyte interphase (SEI): A passivation film formed on the negative electrode by electrolyte reduction, permitting Li⁺ transport while preventing continuous solvent breakdown.

Cathode–electrolyte interphase (CEI): A surface layer on the positive electrode arising from oxidative decomposition of electrolyte components, affecting capacity and impedance.

Solid-state electrolyte (SSE): A non-liquid conductor—ceramic, glass or polymer—that replaces conventional liquid electrolytes to enhance safety and energy density.

Interfacial impedance: The resistance to ionic and electronic transfer across an electrode–electrolyte interface, measurable by electrochemical impedance spectroscopy.

Operando spectroscopy: In situ analytical techniques conducted during electrochemical cycling to observe real-time changes in material chemistry or structure.

References

1. Operando X-ray photoelectron spectroscopy of solid electrolyte interphase formation and evolution in Li2S-P2S5 solid-state electrolytes. Nature Communications (2018).
2. In situ real-time gravimetric and viscoelastic probing of surface films formation on lithium batteries electrodes. Nature Communications (2017).
3. In situ observation of thermal-driven degradation and safety concerns of lithiated graphite anode. Nature Communications (2021).
4. Two electrolyte decomposition pathways at nickel-rich cathode surfaces in lithium-ion batteries. Energy & Environmental Science (2022).
5. Electrolyte Reactivity at the Charged Ni-Rich Cathode Interface and Degradation in Li-Ion Batteries. ACS Applied Materials & Interfaces (2022).
6. Solid–Electrolyte Interphase During Battery Cycling: Theory of Growth Regimes. ChemSusChem (2020).