A very high-energy synchrotron radiation source (87 keV) was utilized for in situ sampling of the structural changes occurring in the electrodic materials of a Li-ion cell during charge-discharge cycling. The real-time evolution of their crystal lattice was obtained as a function of the degree of Li intercalation. As a result, new information on two electrodic materials, Li-Ti "zero strain" and Li-Ni-Co oxide, both of extreme interest for generation of rechargeable batteries, was gained. The actual change of the Li-Ti oxide lattice parameter upon cycling was observed in greater detail than before, and provided evidence of unexpected behavior in some intervals of the cycle. In the Li-Ni-Co sample, a new phase formed during the early stages of cycling that remained stable in the subsequent cycles was revealed. © 2001 American Institute of Physics.

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