Lithium – Pow­er­ing to­day’s tech­nol­ogy Veena Pat­ward­han - Spe­cial Cor­re­spon­dent

Veena Pat­ward­han, Spe­cial Cor­re­spon­dent

Chemical Industry Digest - - What’s In? -

Lithium is an el­e­ment with lim­ited known uses. It is the first metal of the pe­ri­odic ta­ble and also its light­est metal (den­sity around half that of wa­ter). Read about this in­ter­est­ing metal that now plays a key role in the lives of peo­ple world­wide.

Once an el­e­ment with lim­ited known uses, to­day lithium, the first metal of the pe­ri­odic ta­ble and also its light­est metal (den­sity around half that of wa­ter), plays a key role in the lives of peo­ple world­wide. Ever since the Ger­man-born Amer­i­can pro­fes­sor John Good­e­nough de­vel­oped the Lithi­u­mion recharge­able bat­tery in the 1980s, the de­mand for lithium has been grow­ing by leaps and bounds.

In 2014, an­a­lysts de­clared the de­mand was ris­ing by around 12% an­nu­ally. Not sur­pris­ing, given that any portable de­vice you pick, chances are it runs on a lithium-ion bat­tery. Clearly, the light­est metal on earth is no longer a light­weight.

Discovery of lithium

In the 2nd cen­tury AD, the Greek physi­cian So­ranus had writ­ten about the cu­ra­tive prop­er­ties of the min­eral-rich wa­ters of his home­town Eph­e­sus, then a Greek city, for pro­mot­ing men­tal health. He ad­vo­cated that pa­tients suf­fer­ing from ma­nia and melan­cho­lia soak in the wa­ters of these springs. We now know that these wa­ters have high lev­els of lithium salts. The an­cient Greeks like So­ranus had nei­ther iso­lated nor iden­ti­fied lithium, but they had dis­cov­ered the link be­tween the wa­ters of min­eral springs rich in lithium and the treat­ment of manic pa­tients.

The first lithium min­eral, petal­ite, was dis­cov­ered around 1800 on the Swedish is­land of Utö by the Brazil­ian chemist and states­man José Bonifá­cio de An­drada e Silva.

In 1817, a 25-year old Swedish aris­to­crat and chemist Jo­han Au­gust Ar­fved­son, while analysing petal­ite ore in Berzelius’s pri­vate lab in Stock­holm, re­alised he had stum­bled upon a new el­e­ment. He sub­se­quently de­tected the same ma­te­rial in the min­er­als spo­dumene and lep­i­do­lite as well. Ar­fved­son found that the new el­e­ment formed com­pounds sim­i­lar to those of sodium and potas­sium, but that its car­bon­ate and hy­drox­ide were less sol­u­ble in wa­ter and more al­ka­line. The new el­e­ment was named lithium, a name de­rived from ‘lithos’, the Greek word for stone, sig­ni­fy­ing that it had been dis­cov­ered in a solid min­eral un­like other com­mon al­kali met­als that had been dis­cov­ered in plant ma­te­rial.

In 1818, the Ger­man

chemist Chris­tian Gmelin was the first to ob­serve that lithium salts im­part a bright red colour to a flame. Both Ar­fved­son and Gmelin made sev­eral at­tempts to sep­a­rate lithium from its salts but failed. In 1821, the English chemist Wil­liam Thomas Brande suc­ceeded in iso­lat­ing a small quan­tity of lithium by the elec­trol­y­sis of lithium ox­ide, a process Sir Humphrey Davy had pre­vi­ously used for iso­lat­ing the al­kali met­als potas­sium and sodium. To­day, we know that lithium is toxic in larger quan­ti­ties and cor­ro­sive too. But this was not known to the first sci­en­tists at­tempt­ing to study it. In­dica­tive of the times when sci­en­tists were not very vig­i­lant or not overly con­cerned re­gard­ing their safety, in his book A Man­ual of Chem­istry, Brande had writ­ten: “Pure lithia (lithium ox­ide) is very sol­u­ble in wa­ter, and its so­lu­tion tastes acrid like the other fixed al­calis.” He also men­tioned that the el­e­ment lithium had not yet been in­ves­ti­gated be­cause of a dif­fi­culty in procur­ing an ad­e­quate quan­tity of its ox­ide.

In 1855, Robert Bun­sen and Au­gus­tus Matthiessen pro­duced suf­fi­ciently larger quan­ti­ties of lithium through the elec­trol­y­sis of lithium chlo­ride. This paved the way for the com­mer­cial pro­duc­tion of lithium in 1923 by the Ger­man com­pany Me­tallge­sellschaft AG, through the elec­trol­y­sis of a liq­uid mix­ture of lithium chlo­ride and potas­sium chlo­ride.

A soft, sil­very metal lighter than any other, lithium floats on oil and wa­ter. But at­tempt­ing to float it in wa­ter would be a dis­as­ter, for like other al­kali met­als it re­acts vig­or­ously with wa­ter, even mois­ture in the air, pro­duc­ing im­mense heat, and even burst­ing into flames. Lithium is there­fore stored by cov­er­ing it com­pletely in min­eral oil, pe­tro­leum jelly, or any other non-re­ac­tive liq­uid. Its high re­ac­tiv­ity is one rea­son why some lithium-ion bat­ter­ies catch fire or ex­plode at high tem­per­a­tures.

Avail­abil­ity in na­ture

Lithium is a rel­a­tively rare metal present in a con­cen­tra­tion of around 20 parts per mil­lion (ppm) in the earth’s crust, around 0.17 ppm in the oceans and in trace amounts in the at­mos­phere, the food we eat, and in our body. Be­ing highly re­ac­tive, it is not found in the metal­lic, el­e­men­tal state in na­ture, but rather in the form of com­pounds in minute amounts in ig­neous rocks and in the wa­ters of many min­eral springs. The ma­jor min­er­als con­tain­ing lithium in­clude spo­dumene, petal­ite, lep­i­do­lite, and am­bly­go­nite.

Tra­di­tion­ally, lithium is ex­tracted from brine pools or mined from hard rocks. The lat­ter is a time-con­sum­ing, en­ergy-in­ten­sive and costly process for a lot of rock has to be dug out of the earth to get a small amount of lithium. The more eco­nom­i­cal and ef­fi­cient way is by con­cen­trat­ing huge brine pools through so­lar evap­o­ra­tion. Lithium is then pro­duced by the elec­trol­y­sis of molten lithium chlo­ride and potas­sium chlo­ride. In Chile, Ar­gentina, China, Rus­sia, and the US, they use the brine-based ex­trac­tion method.

The brines, that are vol­canic in ori­gin, are found in high al­ti­tude desert re­gions in the form of playas (where the basin sur­face mainly com­prises silts and clays and the brine is un­der­neath) or salars (salt lakes or salt flats where the sur­face is pre­dom­i­nantly salt). Most of the world’s lithium pro­duc­tion takes place in South Amer­ica. The largest brine pool in the world is the salt flat in Bo­livia called the Salar de Uyuni. A fas­ci­nat­ing tourist at­trac­tion, it sits at a height of around 3653m and ex­tends over 12,000 sq. km. and is be­lieved to be one of the most awe-in­spir­ing sights in South Amer­ica.

Var­ied ap­pli­ca­tions: Some flawed, oth­ers favourable

From around the mid-1800s, lithium-rich spa wa­ters were rec­om­mended as a pop­u­lar cure for gout, till this was proved to be more harm­ful than ben­e­fi­cial in 1912.

In the late 1940s, lithium chlo­ride was sold as a salt sub­sti­tute for peo­ple who suf­fered from heart prob­lems and needed to be on a salt-free diet. In 1949, the sud­den death of a num­ber of such pa­tients was found to be caused by lithium poi­son­ing. The treat­ment was im­me­di­ately banned and later the US FDA found that large doses of lithium chlo­ride could ad­verse-

In 1817, a 25-year old Swedish aris­to­crat and chemist Jo­han Au­gust Ar­fved­son, while analysing petal­ite ore in Berzelius’s pri­vate lab in Stock­holm, re­alised he had stum­bled upon a new el­e­ment. Ar­fved­son found that the new el­e­ment formed com­pounds sim­i­lar to those of sodium and potas­sium, but that its car­bon­ate and hy­drox­ide were less sol­u­ble in wa­ter and more al­ka­line. The new el­e­ment was named lithium, a name de­rived from ‘lithos’, the Greek word for stone.

How­ever, the sin­gle most im­por­tant use of lithium in the modern world is in recharge­able lithium-ion bat­ter­ies. With con­sumers de­mand­ing longer-last­ing, lighter, smaller, more pow­er­ful bat­ter­ies for per­sonal de­vices and in­dus­trial equip­ment, lithium was found to be the ideal el­e­ment that could sat­isfy all these mul­ti­ple needs.

ly af­fect the kid­neys.

In the late 1920s just be­fore the on­set of the Great De­pres­sion, a new soft drink called ‘Bib-La­bel Lithi­ated Le­mon-Lime Soda’ was in­tro­duced in the Amer­i­can mar­ket. One of its in­gre­di­ents was lithium cit­rate. To project it as dif­fer­ent from the hun­dreds of other le­mon-lime soft drinks al­ready avail­able in stores, the man­u­fac­tur­ers ad­ver­tised the sup­pos­edly re­fresh­ing health ben­e­fits of the small amount of lithium in the soda. The name of the drink was later short­ened to – hold your breath – ‘7 Up’ which in the 1940s be­came the third best-sell­ing soft drink in the world! The good news for 7 Up fans is that the lithium in the soft drink recipe was dis­con­tin­ued af­ter 1950.

From the 1950s, lithium be­gan to be used as lithium deu­teride, serv­ing as a solid fu­sion fuel in ther­monu­clear weapons, in­clud­ing the hy­dro­gen bomb. Con­se­quently, the de­mand for lithium rose con­sid­er­ably dur­ing the Cold War be­cause of the pro­duc­tion of nu­clear fu­sion weapons. But, its de­mand de­creased by the end of the nu­clear arms race, re­sult­ing in a de­cline in prices of the metal.

Once com­mer­cial pro­duc­tion of lithium com­menced, till around the mid-1990s, the two main ap­pli­ca­tions of the metal in­cluded its use for de­creas­ing the melt­ing tem­per­a­ture of glass and for en­hanc­ing the melt­ing be­hav­iour of alu­minium ox­ide dur­ing the Hall-Héroult process for man­u­fac­tur­ing alu­minium.

Lithium and its com­pounds have a host of other in­dus­trial ap­pli­ca­tions as well. A mag­ne­sium-lithium al­loy is used for ar­mour plat­ing. Alu­minium-lithium al­loys are used for weight re­duc­tion in air­craft, bi­cy­cle frames, and high-speed trains. Its low ther­mal ex­pan­sion co­ef­fi­cient, makes lithium suit­able for pro­duc­ing glass that is re­sis­tant to sud­den heat­ing or cool­ing. It is there­fore used for mak­ing heat-re­sis­tant crock­ery and other spe­cial ce­ram­ics and glasses, in­clud­ing the Mount Palo­mar tele­scope’s 200-inch mir­ror. Lithium stearate is added to pe­tro­leum to make a thick high-tem­per­a­ture lubri­cat­ing grease that is used in the mil­i­tary, and has in­dus­trial, au­to­mo­tive, marine, and air­craft ap­pli­ca­tions. Lithium chlo­ride, one of the most hy­gro­scopic ma­te­ri­als known, is used in air con­di­tion­ing.

In 1949, an Aus­tralian doc­tor John Cade ac­ci­dently found that lithium car­bon­ate could be used to treat manic de­pres­sion or what is now called bipo­lar disor- der, re­in­forc­ing what So­ranus had no­ticed over two mil­len­nia ago. To­day, lithium car­bon­ate pills are the med­i­ca­tion of choice for sta­bil­is­ing mood swings in peo­ple with this disorder.

Lithium-ion Bat­ter­ies

How­ever, the sin­gle most im­por­tant use of lithium in the modern world is in recharge­able lithium-ion bat­ter­ies. With con­sumers de­mand­ing longer-last­ing, lighter, smaller, more pow­er­ful bat­ter­ies for per­sonal de­vices and in­dus­trial equip­ment, lithium was found to be the ideal el­e­ment that could sat­isfy all these mul­ti­ple needs. To­day, lithium is used for mak­ing recharge­able bat­ter­ies for mo­bile phones, dig­i­tal cam­eras, iPods, lap­tops, mp3 play­ers, power tools, grid-scale en­ergy stor­age, and elec­tric ve­hi­cles, and also non-recharge­able bat­ter­ies for heart pace­mak­ers, clocks, and toys.

Cur­rently, Li-ion bat­ter­ies have a cru­cial im­por­tance be­cause of their at­trac­tive com­bi­na­tion of high en­ergy and power den­sity, and also be­cause they help to sig­nif­i­cantly re­duce green­house gas emis­sions. To avoid a pos­si­ble loom­ing short­age in fu­ture, some re­searchers are work­ing on de­vel­op­ing bet­ter ways for re­cy­cling used lithium-ion bat­ter­ies for re­cov­er­ing lithium. Oth­ers are fo­cus­ing on im­prov­ing the en­ergy den­sity and safety of the bat­ter­ies.

Ref­er­ences

1. John Em­s­ley: Na­ture’s Build­ing Blocks: An A-Z Guide to the El­e­ments – Ox­ford Univer­sity Press, 2011

2. Wil­liam Thomas Brande: A man­ual of chem­istry – New York, Pub. by Ge­orge Long, 1821, pp 190

3. Royal So­ci­ety of Chem­istry: Pe­ri­odic Ta­ble – Lithium – http://www.rsc.org/pe­ri­odic-ta­ble/el­e­ment/3/lithium

4. Lee R. McDow­ell: Min­eral Nu­tri­tion His­tory: The Early Years – First Edi­tion De­sign Pub­lish­ing, July 2017, pp 582583

5. El­iz­a­beth Miller: 10 Facts About Lithium – Men­tal Floss, 3 April, 2018

6. Nathan Hurst: Charg­ing ahead: The fu­ture of bat­ter­ies – Smith­so­nian.com, 7 March, 2017, https://www.smith­so­ni­an­mag.com/in­no­va­tion/charg­ing-ahead-fu­ture-of-bat­ter­ies-180962414/

7. Andrew Taran­tola: Where the Most Im­por­tant Part of Your Bat­tery Comes From – Giz­modo, 2 July, 2013, https://giz­modo.com/where-the-most-im­por­tant-part-of-your-bat­tery-comes-fro-586442784

8. Los Alamos Na­tional Lab­o­ra­tory: Pe­ri­odic Ta­ble of El­e­ments – Lithium – http://pe­ri­odic.lanl.gov/3.shtml.

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