Solid-state batteries

In plain language

A typical lithium-ion battery has a liquid electrolyte that carries electric charge between the two electrodes. The liquid is flammable, which is one reason battery fires are a concern. A solid-state battery swaps that liquid for a solid material that still conducts lithium ions.

A solid electrolyte could in principle let the battery store more energy in the same space, especially if the negative electrode is made from pure lithium metal. Building these cells is hard. The workshop report from Oak Ridge National Laboratory lists materials and processing challenges as open problems (Herle and colleagues, 2020).

Technical explanation

In a solid-state cell the liquid electrolyte is replaced with a solid lithium-ion conductor, such as an oxide, a sulfide or a polymer. The most discussed change is a lithium-metal negative electrode, which could raise energy density.

The Oak Ridge National Laboratory workshop report from Herle and colleagues (2020) gives a potential specific energy above 500 Wh/kg and an energy density above 1,500 Wh/L for lithium-metal solid-state batteries over thousands of cycles. The same report groups the materials and processing challenges into four areas: lithium-metal anodes, the solid electrolyte in contact with lithium, cathode materials and composite cathodes, and solid electrolytes themselves.

A University of Maryland project funded through the US Department of Energy aims to use a solid electrolyte that allows lithium-metal anodes with higher energy density, and to prevent the needle-like lithium growths called dendrites that can short a cell (University of Maryland, 2016). The sources reviewed here do not give verified cell-level energy density or cost figures for commercial products.

What the evidence says

Each statement is typed by the strength of its evidence and linked to the source that supports it.

Limitations and open problems

• Composite cathodes are one of the open materials challenges that the workshop report lists as a gap (Herle and colleagues, 2020).
• The workshop report gives potential figures for cells that hold high energy density over thousands of cycles, and the sources reviewed here do not show cells meeting them (Herle and colleagues, 2020).
• Lithium-metal anodes need designs that prevent dendrite growth (University of Maryland, 2016).
• Processing and the mechanical robustness of cells received less attention than materials chemistry in the workshop report, and the authors identify them as gaps (Herle and colleagues, 2020).
• The sources reviewed here do not give verified cost figures for solid-state cells at scale.

Possible future uses

Timeline

1. 18 Aug 2016The University of Maryland announces a US Department of Energy award for work on solid electrolytes for lithium-metal anodes. Sources: [5]
2. 8 Sept 2016Janek and Zeier publish 'A solid future for battery development' in Nature Energy. Sources: [1]
3. 14 Feb 2017Manthiram, Yu and Wang publish a review of lithium battery chemistries enabled by solid-state electrolytes in Nature Reviews Materials. Sources: [3]
4. 2020An Oak Ridge National Laboratory workshop report identifies the materials and processing challenges for high-energy solid-state lithium-metal batteries. Sources: [4]
5. 23 Feb 2023Janek and Zeier publish 'Challenges in speeding up solid-state battery development' in Nature Energy. Sources: [2]

Futures this could help bring about

How far away?

Cheap multi-day energy storage for renewables

Pilots · 2 of 7 steps done

Glossary

Electrolyte

The material between the two electrodes of a battery that carries charged ions while blocking the electrons.

Lithium-metal anode

A negative electrode made of pure lithium metal, which can store more energy than graphite but is harder to control.

Dendrite

A tree-like growth of metal that can form on an electrode during charging and may cause a short circuit.

Energy density

How much energy a battery stores for a given weight or volume.

Sources

1. review article
   A solid future for battery development
   Jürgen Janek, Wolfgang G. Zeier. Nature Energy, 8 Sept 2016. DOI: 10.1038/nenergy.2016.141. Accessed 21 Oct 2026.
2. review article
   Challenges in speeding up solid-state battery development
   Jürgen Janek, Wolfgang G. Zeier. Nature Energy, 23 Feb 2023. DOI: 10.1038/s41560-023-01208-9. Accessed 21 Oct 2026.
3. review article
   Lithium battery chemistries enabled by solid-state electrolytes
   Arumugam Manthiram, Xingwen Yu, Shaofei Wang. Nature Reviews Materials, 14 Feb 2017. DOI: 10.1038/natrevmats.2016.103. Accessed 21 Oct 2026.
4. other
   Challenges for and Pathways Toward Solid-State Batteries
   Subra Herle, Zonghei Chen, Joseph Libera. Oak Ridge National Laboratory, 2020. Accessed 21 Oct 2026.
5. university press release
   DOE Awards $1.25M to UMERC Researchers to Develop Safer, Better Batteries
   University of Maryland, 18 Aug 2016. Accessed 21 Oct 2026.

Revision history

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