# Metal-air batteries: Overview

Batteries that breathe air, built to last for days not hours

Source page: https://www.materialinsights.org/energy/e_metal_air/overview/

What this tile covers Batteries that breathe oxygen from air; iron-air targets multi-day grid storage. Share of use 0% share of world stored energy (2026)

Share of the world's stored energy (energy capacity held, TWh, latest year 2019 to 2026) across the forms with figures, about 22,551 TWh; fuel stocks dominate. Battery and other stores count capacity, not state of charge Form Energy's first grid iron-air systems (for example 1.5 MW / 150 MWh at Great River Energy) slipped to 2027, so almost nothing is in service; zinc-air hearing-aid cells are negligible. Source: [Form Energy: 2026 climate tech companies to watch](https://www.technologyreview.com/2026/10/06/1145020/2026-climate-tech-companies-to-watch-form-energy-iron-batteries/amp/), MIT Technology Review.

#### Key facts

| **Duration** | Days |
|---|---|

#### Included from the reference tables

- Iron-air
- Zinc-air
- Aluminium-air

#### Linked to the material world
[Fe Iron ore](https://www.materialinsights.org/commodities/iron_ore/)[Zn Zinc](https://www.materialinsights.org/commodities/zinc/)[Al Aluminium](https://www.materialinsights.org/commodities/aluminum/)

#### Also in Electrochemical
[LFP Lithium iron phosphate batteries](https://www.materialinsights.org/energy/e_li_lfp/)[NMC Nickel-rich lithium-ion batteries](https://www.materialinsights.org/energy/e_li_nmc/)[SSB Next-generation lithium batteries](https://www.materialinsights.org/energy/e_li_next/)[Na+ Sodium-ion batteries](https://www.materialinsights.org/energy/e_sodium_ion/)[PbA Lead-acid batteries](https://www.materialinsights.org/energy/e_lead_acid/)[NiB Nickel-based batteries](https://www.materialinsights.org/energy/e_nickel_batt/)[VRF Flow batteries](https://www.materialinsights.org/energy/e_flow_batt/)[NaS High-temperature batteries](https://www.materialinsights.org/energy/e_hightemp_batt/)[Zn Other and primary batteries](https://www.materialinsights.org/energy/e_other_batt/)

Explore paths from here
 More on this tile in the tabs above: science and technology, engineering and performance, economics, impact and additionality, what to track.

## Other sections

- [Summary](https://www.materialinsights.org/energy/e_metal_air/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_metal_air/correlation/index.md)
- [Science and technology](https://www.materialinsights.org/energy/e_metal_air/sg-sci/index.md)
- [Engineering and performance](https://www.materialinsights.org/energy/e_metal_air/sg-eng/index.md)
- [Economics](https://www.materialinsights.org/energy/e_metal_air/sg-econ/index.md)
- [Impact and additionality](https://www.materialinsights.org/energy/e_metal_air/sg-impact/index.md)
- [What to track](https://www.materialinsights.org/energy/e_metal_air/tracking/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_metal_air/links/index.md)