Researchers at Sorbonne Université and CNRS synthesized and electrochemically tested five compositions of high-voltage LiCoₓMn₂₋ₓO₄ spinel cathode (x=0, 0.25, 0.5, 0.75 and 1). The October 9 arXiv preprint examined three compositions in detail under identical cycling conditions. The team tracked structural changes during operation using operando X-ray diffraction and X-ray absorption spectroscopy.

In the authors’ analysis, increasing cobalt content reduced the overall volume change from 5.0% to 1.6% by XAS and from 5.8% to 2.1% by XRD. XAS indicated that manganese redox dominated below about 4.7 volts, while cobalt redox became active at higher potentials. The authors conclude that cobalt substitution suppresses electrochemically induced structural strain; the study does not show that this effect improves lifetime or safety in commercial cells. The paper’s first page lists the researchers’ affiliations with Sorbonne Université and CNRS laboratories in Paris. It is a preprint and has not undergone peer review.