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Lithium-ion battery
1991 (Sony); invented 1970s–1985· Invention or discovery· Tools, energy & materials
Well documentedSolid records, physical evidence or scientific consensus.
The light, rechargeable battery that powers phones, laptops and electric cars, first sold by Sony in 1991.
See it on the Technology & Medicine map →How it works
A lithium-ion cell stores energy by moving lithium ions between two layered materials: on charging they pack into a carbon (graphite) electrode, and in use they flow back into a metal oxide, pushing electrons through the device. Stanley Whittingham built an early version at Exxon in the 1970s; John Goodenough found the stronger cobalt-oxide electrode in 1980; Akira Yoshino made a safe working design in 1985. Sony sold the first cells in 1991.
Why it mattered
Light and dense with energy, it made laptops, smartphones and practical electric cars possible; cell prices fell about 97% between 1991 and 2018.
Think of it like
Like tenants moving between two buildings: ions check into the graphite side when charging and move back to the oxide side when used.
How we know
Papers and patents by Whittingham (1976), Goodenough (1980) and Yoshino (1985); Sony's 1991 launch; the 2019 Nobel Prize in Chemistry shared by all three.
Still unknown or debated
Some argue Rachid Yazami's 1980 work on graphite electrodes deserved Nobel credit. Safer, cheaper chemistries such as sodium-ion and solid-state cells are still being tested.
Connections (3)
▸Volta's electric battery is the ancestor of the Lithium-ion batteryMostly agreed
The connection
Volta's 1800 pile showed that two different materials separated by an electrolyte, a conducting liquid or paste, produce a steady current. Every battery since uses that layout. Lithium-ion's advance was using lithium, the lightest metal, shuttling between two layered electrodes, to store far more energy per kilogram and recharge hundreds to thousands of times.
When and how
Volta at Pavia, Italy, announced 1800; lithium-ion developed at Exxon, Oxford and Asahi Kasei in Japan, 1970s–85; first sold by Sony in 1991.
How sure are we?
The shared principle, two electrodes and an electrolyte, is basic electrochemistry; the lineage of battery types between them is well recorded.
Debates and open questions
Calling Volta the 'ancestor' simplifies: lithium-ion relies on 20th-century chemistry, intercalation (ions slotting between layers of a solid), that Volta could not have imagined.
▸Lithium-ion battery powers the SmartphoneWell documented
The connection
A smartphone's screen, radios and processor need lots of power from a thin, light package. Lithium-ion cells, often in flat lithium-polymer pouches, store two or more times the energy per gram of older nickel batteries. That density, plus falling prices, made all-day battery life possible in a slim glass slab.
When and how
Sony's first lithium-ion cells, 1991, went into camcorders and then 1990s mobile phones; every major smartphone since 2007 has used them.
How we know
Phone teardowns and specifications show lithium-ion or lithium-polymer cells in essentially all smartphones.
Debates and open questions
The battery remains the phone's weak point; occasional fires, such as those behind Samsung's 2016 Galaxy Note 7 recall, show the limits of packing in more energy.
▸Lithium-ion battery stores power for Cheap solar, batteries and electric carsWell documented
The connection
Solar and wind produce power only when the sun shines or the wind blows, and cars need stored energy. Lithium-ion batteries address both: pack prices fell about 90% from 2010 to 2023, making electric cars affordable and letting grid-scale battery farms store midday solar for evening use, as in California and Australia.
When and how
Tesla's battery packs from 2008; South Australia's Hornsdale battery, 2017; California's large grid batteries in the 2020s; Chinese makers CATL and BYD now dominate production.
How we know
BloombergNEF's annual battery price surveys; California grid operator data showing batteries supplying a large share of evening demand.
Debates and open questions
Whether lithium supply, cobalt mining conditions and recycling can keep pace, and whether cheaper sodium-ion or longer-duration storage will take over, is debated.