Scientists at the French Geological Survey are working on a way to make the use of lithium traceable so that battery makers could be held accountable if they used unethical sources of it.
A report in the science and technology magazine New Scientist said action was needed because some lithium mines are accused of using excessive fresh water and not respecting indigenous peoples.
Lithium has two stable isotopes— lithium-6 and lithium-7— or atoms of the same element with a different number of neutrons.
The report stated each source of lithium worldwide will have slightly different ratios of these isotopes.
The team looked at previous studies of the isotopic ratios of lithium collected from various mines.
They found lithium sourced from brine deposits has a very different isotopic signature to lithium sourced from hard rock. The heavier isotope – lithium-7 –mixes better with water.