Edison didn't build anything resembling a true lithium battery. Lithium was the salt in his stew. But if nothing else, it was a poetic choice: a century later, after scientists have spent decades scouring the periodic table for better battery materials, we know that lithium is the best possible foundation for electrochemical energy storage. The universe hasn't given us anything better.Lithium, which is now used for purposes as diverse as treating bipolar disorder and strengthening aircraft frames, is one of the three primordial elements, created during the first minutes after the big bang. The lithium atoms in our laptops and cell phones are among the oldest pieces of matter in the universe. Composed of three neutrons, three protons, and three electrons, lithiumreplacement battery for BATBL50L6
is the third element on the periodic table, preceded only by hydrogen and helium. A metal, it is half the density of water and, in its elemental form, too volatile to exist in nature. Pure lithium is silvery-white and soft, like cold Camembert cheese, and must be stored in oil to prevent it from reacting with air or water.
Like its heavier alkali-metal cousins sodium and potassium, lithium was first isolated in the early nineteenth century. In 1800, a Brazilian chemist visiting a mine on the Swedish island of Utö discovered crystalline minerals he named spodumene and petalite, both of which we now know are compounds of aluminum, silicon, and lithium. Seventeen years later, Johan August Arfwedson, a young Swedish chemist working in the lab of Jöns Jacob Berzelius, broke petalite down into a lithium salt, which earned him credit as the discoverer of the element. Berzelius anointed the new mineral, which Arfwedson was never able to isolate in its pure form, "lithos," from the Greek for "stone."
By the mid-1800s, lithium salts were being used medicinally, first to treat gout and, later, all manner of illnesses. Lithium therapy became popular in the late nineteenth century because of the spread of the idea that illnesses ranging from gout to asthma to depression were caused by uric-acid imbalances, and that lithium, by dissolving uric acid, could help with them all. Soon lithium salts and lithiated beverages, products with brand names like Buffalo Lithia Springs Water, were being sold widely as curatives. A brewery in Wisconsin made Lithia Beer using spring water that was high in the mineral. The lithiated drink with the most lasting influence arrived in 1929, with the name Bib-Label Lithiated Lemon-Lime Soda. The Howdy Company of St. Louis marketed the soda, which contained lithium citrate, as a hangover cure. "It takes the ouch out of grouch," went an early slogan. Before long the company founder changed the drink's name to 7-Up Lithiated Lemon-Lime, and today, we know its delithiated progeny as 7UP. (The latest ad campaign: "Ridiculously bubbly!") Lithiated soda might have been dubious, but it was harmless. The next major medical application of lithium was far less benign. In the 1940s, some doctors began giving heart-disease patients lithium chloride as a substitute for their usual sodium-rich salt, and the result was a number of lithium overdoses, several deaths, and a wealth of data on how much lithium it takes to kill a human being. The timing was unfortunate. In 1949, the same year news of the lithium poisoning broke, the Australian psychiatrist John Cade reported dramatic results using safe doses of lithium salts to treat mania. Yet the toxic-overdose episode gave lithium such a bad reputation that the FDA wouldn't approve lithium carbonate as a psychiatric medication until 1970.
Lithium is now one of the most effective pharmaceuticals available for treating mental illness. Mood-stabilizing drugs such as Eskalith, Lithobid, Lithonate, and Lithotabs are indispensible for regulating bipolar disorder. Scientists still aren't exactly sure how they work, but they do know that lithium affects neurotransmitters and cell signaling, and that it increases production of seratonin, the mood-elevating compound whose shortage is associated with depression. (Intriguingly, lithium also seems to stimulate brain-cell growth.) A study published in The British Journal of Psychiatry in 2009, which compared suicide rates and lithium levels in the drinking water of eighteen Japanese towns, found that "even very low levels of lithium in drinking water" — 0.7 to 59 micrograms per liter, compared to the nearly 340 mg of elemental lithium delivered in the commonly prescribed 1,800 mg daily dose of pharmaceutical lithium carbonate — "may play a role in reducing suicide risk within the general population." In an invited commentary piece published in the same issue, a Canadian psychiatrist suggested that lithium could one day be added to drinking water, just as fluoride is added to public water supplies to prevent dental disease. Right away the theory that government eugenicists wanted to exercise mass mind control by lithiating the water supply spread across paranoiac websites.
Despite the significance of lithium as a psychiatric tool, the pharmaceutical industry absorbs only a tiny fraction of the approximately 120,000 metric tons of lithium-bearing compounds that are mined, processed, and sold each year. The largest share goes into metal alloys, ceramics, and lubricating greases, along with various rarefied applications — devices that absorb excess carbon dioxide in the air aboard spacecraft and submarines, rocket propellant, and certain types of nuclear reactors. Because we've stopped replacing the old ones, lithium no longer contributes to the manufacture of thermonuclear weapons. Isotopes of lithium did, however, trigger the largest thermonuclear device the United States ever detonated, the bomb that in the 1954 Castle Bravo test unleashed a blast twelve hundred times more powerful than what hit Hiroshima and Nagasaki, and dusted a swath of inhabited South Pacific islands with radioactive fallout.
Of all of lithium's uses, however, the one with the most profound implications for the future — the application that has already affected the lives of billions of cell-phone-, laptop-, and iPod-using people, and the one that stands to change the way we drive and to transform the way we use energy — is in batteries.
Think of electricity as a stream of electrons. The ideal tool for storing electricity squeezes the largest number of electrons into the smallest and lightest device possible. But you can't just shove loose electrons in a can. To get an electron, you have to pry it loose from an atom. In this way, every electron you get out of a battery comes with baggage in the form of protons and neutrons, both of which are more than eighteen hundred times as massive as an electron. In the lead-acid 12-volt battery under the hood of your car, each usable electron comes tethered to a hefty lead atom — 82 protons and 125 neutrons in the nucleus, for a total atomic weight of 207.2. By contrast, each electron you snatch away from a lithium atom in your cell phone comes with a burden of only 3 protons and 4 neutrons; lithium has an atomic weight of 6.941, thirty times less than that of a lead atom.
A lithium atom's eagerness to shed its outer electron also means that it can be used as the basis for batteries that are more powerful and energy dense than those based on just about any other element. In essence, a battery is a high-energy chemical reaction that has been hijacked into providing useful results rather than a burst of flames. Lithium, recall, is too reactive to exist in nature in its pure form; combine the active ingredients of a lithium-ion battery's two electrodes and, under the right conditions, you have an excellent high explosive. A battery, however, frustrates these violent tendencies. By putting an electrolyte bridge between those two electrodes, a battery keeps those bomb parts at a safe distance from each other, placing an explosion in suspended animation, creating a chemical system throbbing with energy that can be redirected and exploited.
This system, used correctly, can help plug a gaping hole in our technological ecosystem — our pathetically primitive ability to store energy. As Bill Gates put it in a 2010 speech, all the batteries in the world can together store only ten minutes of our global electrical needs. In an era of grave concern about the future of energy, this is a fairly obscene weakness.
Today we power our cars almost exclusively by burning the fossilized remains of prehistoric plankton, transforming the energy that holds those hydrocarbon molecules together into energy that moves us around town. And oil has many advantages: it's powerful, versatile, and easy to store — we can simply put it in a barrel or a gas tank and let it sit. Yet oil's many consequences (environmental degradation, greenhouse-gas emissions, the enrichment of dictators and sworn enemies of civilization), combined with the fact that we will eventually run out of affordable sources, make finding alternatives an obvious imperative.
Of the alternatives, electricity is the cleanest and most flexible option. It's piped into every home in the country. Mile by mile, it's cheap compared with gasoline. It's far more feasible than hydrogen, and in almost all circumstances it's cleaner than ethanol. It can come from almost any source — natural gas, coal, nuclear, hydroelectric, solar, wind. Even when it is generated by a coal-burning power plant, it still produces less carbon dioxide per mile than a mile powered by gasoline.The problem is, electricity is hard to store, and that's why the lithium-ion battery has attracted so much attention. It has already proved itself to be a powerful driver of modernity. Largely because of the arrival of the lithium-ion battery in the early 1990s, the cellular telephone first became ubiquitous and then transformed into a pocketable computer. Then it became a computer that connects wirelessly to the Internet. Then it became a computer, camera, MP3 player, GPSv12 cells AS07B41
navigator, movie player, and all-around life planner and time waster, extending the reach of the information revolution into our pockets.
Now, the hope is that lithium-ion and, later, even more advanced batteries can both make electricity a viable transportation fuel and help fill the gaps in the electrical grid that are currently stifling the implementation of renewable energy sources. Already companies are building tractor-trailer size lithium-ion battery banks and hooking them up to wind and solar farms. The ability to store intermittent sources of energy like these (the sun goes down at night, the wind doesn't always blow) makes them vastly more practical and affordable as alternatives to polluting sources such as coal.
This is the kind of transformation that the scientists who laid the intellectual foundation for the rechargeable lithium battery had in mind. They were motivated by both scientific curiosity and big-picture social concerns. They began working on the vexing problem of energy storage more than four decades ago, in an age of scarcity and uncertainty much like our own.
