Geothermal brines represent a vast source of lithium (Li) resources for use in battery manufacturing. Capturing this resource has proven energy- and cost-intensive, as the Li must be isolated from the calcium, magnesium and other ions present in the brine. A separation solution devised at Rice University reduces these challenges encountered in Li harvesting operations.

The three-chambered electrochemical reactor incorporates a Li-ion conductive glass ceramic membrane, similar to those commonly placed in Li-ion batteries, in its center. This component selectively allows Li to pass through while blocking other ions. The high ionic conductivity of the reactor enhances its efficiency for this application while also reducing the production of potentially hazardous chlorine gas.

Test results reported in the Proceedings of the National Academy of Sciences confirm a 97.5% Li purity rate for the new reactor design. The membrane proved effective at letting only Li ions pass through while holding back ions of the other chemicals, especially undesirable chloride ions. The researchers are confident that the selective membrane-equipped system represents a more environmentally sustainable, efficient and potentially faster method for extracting Li from geothermal brines.