Their own comparison shows the index matching or beating the Lithium ETF in every metric.
* LIT since inception: 38.48%
* Index over same period: 45.82%
You also have zero diversification with a resource ETF. If you really want to buy into only Lithium then I won't try to talk you out of it.
But maybe consider Vanguard Growth ETF (VUG), the average return over 5 years is 14.4%, or nearly double that of LIT. [1]
[1] https://institutional.vanguard.com/iippdf/pdfs/FS967R.pdf