Silver Lithium Seawater

Lithium has become a highly sought-after element mainly because of its growing use in batteries that provide a lot of power for relatively little weight compared to traditional batteries usually made from lead and zinc. However, we are using lithium at a fast rate. U.S. Geological Survey (USGS) data indicated that more than 70 percent of lithium mined was used in batteries in 2020, up more than 23 percent from 2010 when the rare metal was mainly used in making glass and ceramics. Some analysts predict that manufacturers could consume about one-third of the lithium supply in just a few decades — land-based lithium, at least.

Seawater also contains lithium, and silver is helping to extract it. Lithium may be thousands of times more plentiful in seawater than it is on land, according to the USGS, which estimates that there are 200 billion metric tons of lithium in oceans compared to about 21 million tons currently obtainable using standard land-based mining methods.

Several methods of seawater extraction are being tested, but one technique from Seoul National University (SNU), South Korea, holds promise, and silver is a component. The salt-enriched by-product of taking saltwater and turning it into potable water — a method known as desalinization — leaves behind a great deal of salt and small amounts of lithium. By using an electrolysis-type of system with pairs of silver and manganese oxide electrodes, scientists were able to raise the natural concentration of lithium in the mostly-salt piles.

“In this study,” wrote lead author Hwajoo Joo, of the School of Chemical and Biological Engineering and Institute of Chemical Processes (ICP) at SNU, “using lithium-ion battery electrode materials [made from manganese oxide and silver electrodes] enabled lithium recovery from 6 tons of desalination concentrate per day (0.25 ton per hour) … with purity of 88 percent and enrichment factor of 1,800.”

And, while this method yields small absolute amounts of lithium, the United Nations estimated in 2019 that the world’s 16,000 plants produced about 5 billion cubic meters of brine every day, of which 5 percent is salt and other chemicals including lithium, compared to seawater which contains about 3.5 percent salt and other chemicals depending upon the body of water.