Comment on: A Mangrove-Inspired Off-Grid System Integrating Electrodialysis and Photothermal Evaporation for Direct Lithium Salt Extraction from Brine

An artificial mangrove for the lithium age. Every electric car, every grid battery, every phone in every pocket runs on lithium. The trouble is that demand is climbing faster than the supply, and much of what counts as “supply” still comes from a process that would look oddly familiar to a salt-maker two thousand years ago: pump salty water out of the ground, spread it across vast, shallow desert ponds, and wait for the sun. Then there is the long wait of one to two years. The ponds sprawl across tens of square kilometers, visible from space. They drink groundwater in some of the driest parts of the planet, require chemicals at several stages, and even then, about half the lithium is discarded with the leftover brine. What emerges is not a finished product at all. It must be filtered, precipitated, and purified through yet more steps—each one consuming energy and shedding more of the metal along the way. The bottleneck is separation. Lithium has to be prised away from other metal salts dissolved in seawater. In brine, lithium is outnumbered by sodium, and, worse, by magnesium. Lithium and magnesium sit next to each other diagonally in the periodic table and behave so similarly in water that telling them apart is like trying to sort two nearly identical grains of sand by hand, several million times over...