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
is between 0.1 and 0.7 wt %
wt %
carbonate precursor
sulfur content
is between 0.2 and 0.9 wt %
wt %