# Lead-acid batteries

The old workhorse of car starters, UPS units and home inverters.

Source page: https://www.materialinsights.org/energy/e_lead_acid/

Storage · Electrochemical · No. 72

- Storage
- Duration: Hours
 Storage · Electrochemical · Foundation · Energy

The battery under your car bonnet has the best recycling loop of any battery, yet careless recycling poisons children.

Chart: Illustration: Lead-acid batteries

##### Where it comes from

Chart: Map of where it comes from

Two plates of lead and lead dioxide sit in sulphuric acid and turn into lead sulphate as they discharge; the EU will require 85% recycled lead from 2031.

##### Three things to know

1. Lead-acid stores only 25 to 50 Wh/kg, against 150 to 300 for lithium-ion, so it is heavy for its energy.
2. Up to half of lead-acid batteries in poorer countries are recycled informally, spreading a neurotoxin into soil, air and blood.
3. Its water-based acid cannot burn, so US fire rules only apply above about 70 kWh, against 20 kWh for lithium-ion.

##### The journey

1. 1 **Lead and acid**Mostly recycled lead, dilute sulphuric acid
2. 2 **Plates**Lead dioxide and spongy lead plates
3. 3 **Discharge**Both plates turn into lead sulphate
4. 4 **Backup duty**Car starters, UPS, telecom, home inverters
5. 5 **Recycling**Smelted again, safely or informally
 Covered in [Reserves, stocks and depletionCommodities](https://www.materialinsights.org/learn/commodities/reserves-stocks-depletion/)[Storing energy: from fuel stocks to batteriesEnergy](https://www.materialinsights.org/learn/energy/storing-energy/)

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## Other sections

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