Cornish Lithium has raised £6mln in a crowdfunding round that took less than 20 minutes.
The battery metals specialist raised the money through Crowdcube at a price that values the group at £80mln, double the level of its previous funding in October last year that raised £5.2mln.
Jeremy Wrathall, a former Investec analyst, said the new funds "will be used to continue the progress towards our goal of creating a battery metals hub for the UK".
Cornish Lithium is aiming to produce the metal both from geothermal waters extraction and from a hard rock project near St Austell.
Wrathall believes supplies are sufficient to meet the UK's entire requirement for lithium carbonate once the country switches to electric vehicles from 2030.
Cornish Lithium has already gathered together a sizeable land package and is confident that when the appropriate tests are complete and the time comes to start commercial extraction, it will be able to produce the lion’s share of the lithium in brines that Cornwall ends up producing.
In the background, there are also hard rock mines, but for now the brines are the focus because the footprint is so small and the upside is so great.