Solid Electrolyte Interphase Dynamics in Lithium-Ion Battery Systems

The solid electrolyte interphase (SEI) is a nanometre-thin passivation layer that forms spontaneously on the negative electrode of a lithium-ion cell during its initial cycles. Its composition, structure and morphology evolve continuously under cycling and temperature stress, directly influencing lithium-ion transport, electronic insulation and mechanical stability. SEI dynamics govern critical performance metrics such as capacity retention, rate capability, safety and calendar life. The interplay between electrolyte formulation, electrode materials and formation protocols determines the balance of organic and inorganic SEI constituents, the prevalence of grain boundaries and the propensity for crack formation. Advances in in situ probing and multiscale simulation have begun to unravel the kinetic and mechanochemical processes underpinning SEI growth, self-repair and degradation. Understanding these processes is essential for designing high-energy-density batteries with rapid-charge capability and extended lifetime, thereby supporting the deployment of electric vehicles and grid-scale storage.

Research from Nature Portfolio

Recent studies have visualised SEI nucleation and growth with in situ atomic force microscopy on cross-sectioned electrodes, enabling direct comparison of highly oriented pyrolytic graphite, microbead graphite and hard carbon substrates. These observations reveal that the onset potential for SEI formation, the layer adhesion and the mechanical resilience correlate strongly with electrode surface roughness and crystallinity. The work also demonstrates the absence of analogous passivation on positive-electrode materials, highlighting fundamental differences in interfacial stabilisation mechanisms. In parallel, molecular dynamics investigations of a model SEI comprising dilithium ethylene dicarbonate have characterised three distinct lithium-ion transport regimes—ballistic, trapping and diffusive—consistent with glassy behaviour. The results show that nanosecond-scale trapping in the SEI dominates transport resistance but diminishes at higher temperatures, suggesting that new electrolyte additives or artificial interphases should target reduced trapping volumes to accelerate charging.

Research from all publishers

First-principles kinetic Monte Carlo simulations have integrated electrolyte reduction reactions with diffusion events to model SEI formation and lithium electrodeposition on metal anodes. These dynamic simulations capture the competition between organic and inorganic components and demonstrate that grain boundaries within the SEI serve as fast pathways for ion transport, underscoring the importance of microstructural control for stability and performance. A comprehensive review of lithium-ion cell formation highlights the interdependence of material selection, electrolyte composition and formation protocols in shaping SEI composition and uniformity; it surveys emerging experimental techniques and predictive simulation tools for tailoring the formation step in next-generation cells. Data-driven reaction network modelling has further expanded mechanistic insight by constructing massive stoichiometrically consistent networks of thousands of species and millions of reactions. Automated pathway analysis within these networks has identified both classical and previously unreported routes to key SEI components, illustrating the potential of large-scale computational frameworks to guide rational design of interphase chemistry.

Solid Electrolyte Interphase Dynamics in Lithium-Ion Battery Systems publication trend

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

Technical terms

Solid Electrolyte Interphase (SEI): A passivation layer of inorganic and organic decomposition products that forms on the anode surface and regulates lithium-ion and electron transport.

Passivation Layer: A thin film that protects the electrode from continuous electrolyte decomposition by providing electronic insulation while permitting ion conduction.

First-Principles Kinetic Monte Carlo (kMC): A simulation approach combining quantum-mechanical reaction energetics with stochastic modelling of diffusion and reaction events over extended timescales.

Reaction Network Modelling: A computational framework that represents chemical processes as graphs of species and reactions, enabling identification of low-energy pathways through automated algorithms.

Ballistic, Trapping and Diffusive Regimes: Distinct transport behaviours observed in ion-conducting media, where ions move freely (ballistic), become temporarily immobilised (trapping) or wander randomly (diffusive).

References

1. Solid-electrolyte interphase nucleation and growth on carbonaceous negative electrodes for Li-ion batteries visualized with in situ atomic force microscopy. Scientific Reports (2020).
2. Molecular Dynamics of Lithium Ion Transport in a Model Solid Electrolyte Interphase. Scientific Reports (2018).
3. SEI Formation and Lithium-Ion Electrodeposition Dynamics in Lithium Metal Batteries via First-Principles Kinetic Monte Carlo Modeling. ACS Energy Letters (2024).
4. Lithium-ion battery cell formation: status and future directions towards a knowledge-based process design. Energy & Environmental Science (2024).
5. A chemically consistent graph architecture for massive reaction networks applied to solid-electrolyte interphase formation. Chemical Science (2021).