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7 5 I H I G H L I G H T S 2 0 2 57 4 H I G H L I G H T S 2 0 2 5 I
PRINCIPAL PUBLICATION
Mapping Reaction Mechanism During Overcharge of a LiNiO2/Graphite–Silicon Lithium-Ion Battery: A Correlative Operando Approach by Simultaneous Gas Analysis and Synchrotron Scattering Techniques, Q. Jacquet et al., Adv. Energy Mater. 15(15), 2404080 (2025); https:/doi.org/10.1002/aenm.202404080
REFERENCES
[1] D. Atkins et al., Adv. Energy Mater. 12, 2102694 (2022). [2] L. de Biasi et al., ChemSusChem 12, 2240 (2019). [3] C.L. Berhaut et al., ACS Nano 13, 11538 (2019).
and nanoscale morphology. By providing direct correlations rather than separate measurements, the technique resolves long-standing uncertainties regarding phase formation mechanisms. These unprecedented insights into multi-scale battery phenomena enable development of more accurate predictive degradation models, informing the design of safer next-generation energy storage devices. The technique can be extended to other electrochemical systems where gas release affects performance, opening new research directions for post-lithium-ion batteries. This advanced coupling between lab-scale and synchrotron techniques using standardised data acquisition and analysis protocols is a major goal and achievement of the Pilot Battery Hub at the ESRF.
Fig. 60: Evolution during overcharge of the graphite interlayer distance, c parameter of LixNiO2, SAXS integrated intensity, and gas evolution for specific mass fragments. For all plots except gas analysis, data from different positions in the pouch cell are shown: centre (orange), reference (brown), edge (purple), and GrSi-only (green). The black curve represents the average over the entire electrode, while the blue curve indicates the full-cell voltage profile. The top panel shows a transmission image of the pouch cell with the selected positions and the LNO electrode borders (red dotted line). Horizontal lines serve as visual guides for lattice parameter and SAXS intensity variations during the voltage hold at 5 V; vertical grey dotted lines mark the end of the charge (before the hold) and the onset of discharge.
The results revealed that CO2 and O2 evolution from LiNiO2 occurs immediately after the H2-H3 structural phase transition (Figure 60). Despite the presence of O2, the formation of the O1 phase – a layered structure similar to LiNiO2 but with a different stacking sequence that is associated with the degradation of LiNiO2 – was not detected. SAXS intensity increases correlated with both structural densification and gas release, indicating coupled atomic and nanoscale changes. Gas production was also found to create spatially heterogeneous electrode reactions, with some regions exhibiting delayed kinetics.
This correlative operando approach transforms battery characterisation by revealing the previously hidden connections between gas evolution, structural changes,
