5. The carbonate precursor compound of claim 1, wherein the sodium content is between 0.1 and 0.7 wt% and the sulfur content is between 0.2 and 0.9 wt%.
carbonate precursor
sodium content
between 0.1 and 0.7 wt%
wt%
carbonate precursor
sulfur content
between 0.2 and 0.9 wt%
wt%