Chemistry and structure analysis in the Li4 + xBxSi1 − xO4 solid solution

The crystal chemistry of the Li4SiO4-based solid solution Li4+xBxSi1−xO4 is presented. Synthesis was carried out using LiOH·H2O or Li2CO3 as starting materials. Stoichiometric mixtures with 0≤x≤0.7 were fired at temperatures ranging from 670 to 850 °C. A CO2-free atmosphere is required to avoid the presence of Li2CO3 in the remaining solid. Small amounts of LiOH are detected in samples prepared from LiOH·H2O. The solubility of boron in the solid solution is also discussed in terms of crystal structure analysis. The lithium insertion is accompanied with a continuous slight increase in the unit-cell volume. x=0.5 is the maximum composition above which Li+ insertion should be accompanied with a modification of the Li4SiO4-based structure.