High precision studies of lattice parameter changes in lithium intercalation compounds

We present an in situ X-ray diffraction experiment which measures lattice parameter changes resulting from lithium intercalation to a precision of one part in 10⁵. Experiments on 2H-Li_xTaS₂ demonstrate the sensitivity and reproducibility of the method. To our knowledge, these results are the most precise measurments of lattice parameter changes resulting from intercalation. We find that the c-axis of 2H-Li_xTaS₂ exhibits anomalous behaviour near $\text{x=}\text{1}\text{3}$ and $\text{x=}\text{2}\text{3}$ pr esumably because of the order-disorder transitions in the intercalated lithium.