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Material World
Object

Lithium-ion cell

Lithium ions shuttling between two hosts — and the object that turned a list of obscure elements into a geopolitical argument.

A lithium-ion cell stores energy by moving lithium ions between two materials that can host them: a layered oxide cathode and, almost always, a graphite anode. Nothing is consumed and nothing plates out — the ions intercalate between atomic layers and come back — which is why the cell is rechargeable and why it lasts for hundreds of cycles.

Its materials are the whole argument about it. The cathode carries the cobalt, nickel and manganese; the anode is graphite, which is unglamorous and is the largest component by mass after the cathode; the electrolyte is a lithium salt in an organic solvent, which is flammable and is why thermal runaway is the failure mode people know about.

History

The intercalation principle is Stanley Whittingham's in the 1970s; John Goodenough's cobalt oxide cathode in 1980 gave the voltage; Akira Yoshino's carbon anode in 1985 made it safe enough to sell, because lithium metal anodes grow dendrites and short. Sony commercialised it in 1991. The three shared the 2019 Nobel Prize in Chemistry.

Cathode chemistry has moved steadily away from cobalt — nickel-rich compositions and lithium iron phosphate — and the reason is supply and ethics as much as performance, with a large share of cobalt coming from the Democratic Republic of the Congo under conditions that are a persistent and documented problem.

Cultural significance

It is the object that made portable computing and then electric vehicles possible, and the one that turned lithium, cobalt, nickel and graphite from industrial commodities into subjects of national policy.

It is also where the materials transition argument becomes concrete. A grid and a vehicle fleet built on storage need a large quantity of specific elements up front in exchange for not needing fuel afterwards, and whether that is a good trade is a question about mining, recycling and time rather than a question about batteries.

Medium confidence Weak evidence

How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.

How this connects

Where a connection has been confirmed by an outside reference, that reference is named beside it.

is made of

  • Lithium — element · the ion that shuttles, and the only part of the cell the name mentions
  • Cobalt — element · in the cathode of the older chemistries, and the component the industry has been designing away from
  • Nickel — element · in the cathode, and increasing as cobalt falls
  • Graphite — mineral · the anode, unglamorous and the largest component by mass after the cathode
  • Lithium iron phosphate — compound · in more than half of world cell production, and in almost all stationary storage — the cathode chosen where mass does not bind and price and fire risk do
  • NMC cathode — compound · in long-range vehicles and anything that has to be carried, where the requirement is energy per kilogram and no phosphate cathode competes
  • Lithium cobalt oxide — compound · in the smallest cells only — phones, laptops, cameras — where volume is the constraint and a few hundred cycles is a long enough life
  • Battery graphite — material · the anode of essentially every cell ever sold, and roughly twice the mass of the cathode it is paired with

is used in

  • Energy generation — industry · grid storage and electric vehicles, which is what turned a list of obscure elements into a geopolitical argument
  • Electronics manufacture — industry · and portable computing came first by two decades

is used as

is made using

  • Salt — compound · not directly — but the chlor-alkali chlorine goes into the solvents and the caustic soda into the cathode precursor, which is the kind of dependency a supply chain only notices when it breaks

Sources

  • Wikidata
    Wikimedia Foundation · Creative Commons CC0 1.0 Universal (public domain dedication)
  • Material World
    Our own writing

Questions this page answers

Where it comes from, and what it becomes

Follow Lithium-ion cell back to what it starts as, and forward into what it becomes. Each step is a documented one — a real route material takes, not a chain of inference.

Upstream — what it comes from

  • Lithium-ion cell → is made of (in the cathode of the older chemistries, and the component the industry has been designing away from) → Cobalt → is sourced from (much of world supply arrives as a by-product of copper mining rather than from cobalt-first operations) → Copper → is produced by (as blister copper, refined electrolytically afterwards) → Smelting → takes as input (as the element removed, not added) → Oxygen → is produced by (the largest output by tonnage, and the reason air separation units sit beside steelworks) → Air separation
  • Lithium-ion cell → is made of (the ion that shuttles, and the only part of the cell the name mentions) → Lithium → is produced by (the majority of world supply, concentrated over a year or more in ponds on the Andean salars from a few hundred parts per million to a few per cent) → Brine evaporation → takes as input (and the pond sequence is run so that the less soluble salts crystallise out first, leaving the sodium chloride to be harvested on its own) → Salt → is sourced from (by solar evaporation, which needs a dry sunny coast and is the cheapest route there is) → Seawater → is composed of (about 96.5 per cent by mass — seawater is 3.5 per cent dissolved solids and the rest of it is this) → Water
  • Lithium-ion cell → is made of (in the cathode, and increasing as cobalt falls) → Nickel → is produced by (reduced from roasted pentlandite concentrate, with the platinum-group metals following into the refinery) → Smelting → takes as input (as the element removed, not added) → Oxygen → is produced by (the largest output by tonnage, and the reason air separation units sit beside steelworks) → Air separation → takes as input (the feedstock, and an unusual one in being free, unlimited and available anywhere — the cost is entirely the energy to liquefy it) → Air
  • Lithium-ion cell → is made of (in more than half of world cell production, and in almost all stationary storage — the cathode chosen where mass does not bind and price and fire risk do) → Lithium iron phosphate → is produced by (lithium, iron and phosphate precursors fired together under an inert atmosphere, with a carbon source that leaves the conductive coating each particle needs) → Calcination → takes as input (heated until the carbonate decomposes to lime and carbon dioxide) → Limestone → is sourced from (precipitated from it, mostly by organisms building shells and skeletons out of dissolved calcium and carbonate) → Seawater → is composed of (about 96.5 per cent by mass — seawater is 3.5 per cent dissolved solids and the rest of it is this) → Water
  • Lithium-ion cell → is made of (in long-range vehicles and anything that has to be carried, where the requirement is energy per kilogram and no phosphate cathode competes) → NMC cathode → is produced by (a mixed hydroxide precursor co-precipitated first so the three metals are evenly distributed, then fired with lithium — and the precursor step is where most of the quality is decided) → Calcination → takes as input (heated until the carbonate decomposes to lime and carbon dioxide) → Limestone → is sourced from (precipitated from it, mostly by organisms building shells and skeletons out of dissolved calcium and carbonate) → Seawater → is composed of (about 96.5 per cent by mass — seawater is 3.5 per cent dissolved solids and the rest of it is this) → Water
  • Lithium-ion cell → is made of (in the smallest cells only — phones, laptops, cameras — where volume is the constraint and a few hundred cycles is a long enough life) → Lithium cobalt oxide → is produced by (lithium carbonate and cobalt oxide fired together, which is the simplest of the cathode syntheses and part of why it was first) → Calcination → takes as input (heated until the carbonate decomposes to lime and carbon dioxide) → Limestone → is sourced from (precipitated from it, mostly by organisms building shells and skeletons out of dissolved calcium and carbonate) → Seawater → is composed of (about 96.5 per cent by mass — seawater is 3.5 per cent dissolved solids and the rest of it is this) → Water

These are the most distinct paths back. Lithium-ion cell can be traced through others besides.

Downstream — what it becomes