CHEMISTRY AND STRUCTURE-ANALYSIS IN THE LI4-XO4 SOLID-SOLUTION(XBXSI1)

The crystal chemistry of the Li4SiO4-based solid solution Li4+xBxSi1+x O4 is presented. Synthesis was carried out using LiOH . H2O or Li2CO3 as starting materials. Stoichiometric mixtures with 0 less than or equ al to x less than or equal to 0.7 were fired at temperatures ranging f rom 670 to 850 degrees C. A CO2-free atmosphere is required to avoid t he presence of Li2CO3 in the remaining solid. Small amounts of LiOH ar e detected in samples prepared from LiOH . H2O. The solubility of boro n in the solid solution is also discussed in terms of crystal structur e analysis. The lithium insertion is accompanied with a continuous sli ght increase in the unit-cell volume. x=0.5 is the maximum composition above which Li+ insertion should be accompanied with a modification o f the Li4SiO4-based structure.