Lithium-ion (Li-ion) batteries have become the energy storage solution of choice for portable electronic devices such as laptops and smart phones. The emergence of electric and hybrid vehicles has furthered interest in new battery technologies that offer improved performance. Electric and hybrid electric vehicle manufacturers are driving demand for lithium, graphite, and cobalt, the three primary components needed to make rechargeable lithium batteries.
Companies such as Tesla Motors plan to build Li-ion battery “gigafactories,” raising the question of whether or not there are enough of these natural resources to accommodate the demand, as explained in last year’s post, Growth for Graphite? Emerging Applications May Influence Demand. We can ask the same question about lithium- where will it all come from?
Lithium is a common but poorly concentrated mineral. Because traditional hard-rock mining of lithium-bearing pegmatite and spodumene is a costly and time-intensive endeavor, most lithium is produced by the evaporation of highly concentrated lithium brine, an easier and more profitable method. Almost all of the world’s brine deposits are in South America. The hard rock minerals pegmatite and spodumene are found mainly in Australia. The Industrial Minerals website explain the two methods:
- Surface brines: Brine is pumped from subsurface reservoirs to surface ponds. The sun evaporates excess water and concentrates the mineral content of the brine. Once the lithium content reaches 6%, the liquor is removed and processed into lithium chemicals.
- Hard rock mining: Spodumene or pegmatite is mined and crushed to form a concentrate. This mineral concentrate is then sold to chemical companies to be used as feedstock to produce lithium chemicals or to glass and ceramics producers to be used as an additive.
According to the U.S Geological Survey’s 2015 Lithium Mineral Commodity Summary, while surface brines were the dominant raw material for lithium carbonate production in the 1990s, mineral-sourced lithium regained market share in the past several years thanks to growing demand from China, and was estimated to account for one-half of the world’s lithium supply in 2014. The report states that worldwide lithium production increased by about 6% in 2014. Production from Argentina and Chile increased approximately 15% each in response to increased lithium demand for battery applications.
Other potential sources of lithium are hectorite clay, jadarite, geothermal brine, oilfield brine, and seawater. The MIT Technology Review reports that researchers at Japan’s Atomic Energy Agency are developing a method of processing seawater to extract lithium using dialysis, although this process is still years from commercialization. The study was originally published in the journal Desalination. The U.S. Geological Survey reports that hectorite clays are the third most important source of lithium, after continental brines and pegmatites. The Kings Valley deposit in Nevada is being developed in part to extract lithium for the electric vehicle market. The only other commercially developed source of hectorite is a mine at Newberry Springs, California.
In addition to increasing the supplies of raw materials needed to make lithium-ion batteries, there is considerable interest in further improving the performance of Li-ion cells, for example to increase energy density, reduce weight, decrease costs, and improve recharge times. Read the next installment to learn about X-ray photoelectron spectroscopy (XPS) as an investigative tool to improve Li-ion battery technology.