80
5 Conclusion
Sodium is a globally abundant, inexpensive, and high energy density material that
has an established precedent and promising future as the basis for a family of gridscale batteries. With a moderate melting temperature, molten sodium offers distinct
advantages in terms of electrochemical kinetics and flexibility of battery form
design. Traditionally elevated operating temperatures of Na–S and Na–NiCl 2 batteries, however, contribute to market-limiting costs and may need to be overcome to
enable the widespread utility of this technology. Widely varied potential cathode
chemistries offer opportunities to lower operating temperatures, increase voltages,
extend battery lifetimes, and reduce system costs. In addition, advancements made
toward lower temperature, high conductivity separator materials will further drive
down operating temperatures and improve both the reliability and performance of
sodium batteries. Innovations in the materials chemistries of these batteries will also
inform novel cell designs that optimize chemical and electrochemical properties of
emerging systems to drive the technology forward. Meanwhile, current deployments of Na–S and Na–NiCl 2 battery systems, based on traditional high temperature
systems, enable a wide range of grid-scale services around the globe with promise
toward continued expansion as technical and market advances drive down costs and
create opportunities for these technologies. Active research and forward-thinking
development present great promise for a new generation of safe, reliable, long-lived
grid-level energy storage technologies.
Acknowledgements The authors were supported through the Energy Storage Program, managed
by Dr. Imre Gyuk in the U.S. Department of Energy Office of Electricity. Sandia National
Laboratories is a multimission laboratory managed and operated by National Technology &
Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International
Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract
DE-NA0003525. This paper describes objective technical results and analysis. Any subjective
views or opinions that might be expressed in the paper do not necessarily represent the views of the
U.S. Department of Energy or the United States Government.
References
1. Kummer JT, Neill W (1968) Secondary battery employing molten alkali metal reactant.
U.S. patent no. 3,404,035
2. Werth JJ (1975) Alkali metal-metal chloride battery. U.S. Patent No. 3,877,984
3. FZSoNick. FZSoNick battery applications. https://www.fzsonick.com/applications
4. EPRI (2010) Electric energy storage technology options: a white paper primer on applications,
costs, and benefits. EPRI, Palo Alot, CA
5. Fan L, Wei S, Li S, Li Q, Lu Y (2018) Recent progress of the solid-state electrolytes for highenergy metal-based batteries. Adv Energy Mater 8:1702657
6. NGK Insulators. NAS case studies. https://www.ngk.co.jp/nas/case_studies/
7. Vesborg PCK, Jaramillo TF (2012) Addressing the terawatt challenge: scalability in the supply
of chemical elements in renewable energy. RSC Adv 2:7933–7947
E. D. Spoerke et al.
5 Conclusion
Sodium is a globally abundant, inexpensive, and high energy density material that
has an established precedent and promising future as the basis for a family of gridscale batteries. With a moderate melting temperature, molten sodium offers distinct
advantages in terms of electrochemical kinetics and flexibility of battery form
design. Traditionally elevated operating temperatures of Na–S and Na–NiCl 2 batteries, however, contribute to market-limiting costs and may need to be overcome to
enable the widespread utility of this technology. Widely varied potential cathode
chemistries offer opportunities to lower operating temperatures, increase voltages,
extend battery lifetimes, and reduce system costs. In addition, advancements made
toward lower temperature, high conductivity separator materials will further drive
down operating temperatures and improve both the reliability and performance of
sodium batteries. Innovations in the materials chemistries of these batteries will also
inform novel cell designs that optimize chemical and electrochemical properties of
emerging systems to drive the technology forward. Meanwhile, current deployments of Na–S and Na–NiCl 2 battery systems, based on traditional high temperature
systems, enable a wide range of grid-scale services around the globe with promise
toward continued expansion as technical and market advances drive down costs and
create opportunities for these technologies. Active research and forward-thinking
development present great promise for a new generation of safe, reliable, long-lived
grid-level energy storage technologies.
Acknowledgements The authors were supported through the Energy Storage Program, managed
by Dr. Imre Gyuk in the U.S. Department of Energy Office of Electricity. Sandia National
Laboratories is a multimission laboratory managed and operated by National Technology &
Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International
Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract
DE-NA0003525. This paper describes objective technical results and analysis. Any subjective
views or opinions that might be expressed in the paper do not necessarily represent the views of the
U.S. Department of Energy or the United States Government.
References
1. Kummer JT, Neill W (1968) Secondary battery employing molten alkali metal reactant.
U.S. patent no. 3,404,035
2. Werth JJ (1975) Alkali metal-metal chloride battery. U.S. Patent No. 3,877,984
3. FZSoNick. FZSoNick battery applications. https://www.fzsonick.com/applications
4. EPRI (2010) Electric energy storage technology options: a white paper primer on applications,
costs, and benefits. EPRI, Palo Alot, CA
5. Fan L, Wei S, Li S, Li Q, Lu Y (2018) Recent progress of the solid-state electrolytes for highenergy metal-based batteries. Adv Energy Mater 8:1702657
6. NGK Insulators. NAS case studies. https://www.ngk.co.jp/nas/case_studies/
7. Vesborg PCK, Jaramillo TF (2012) Addressing the terawatt challenge: scalability in the supply
of chemical elements in renewable energy. RSC Adv 2:7933–7947
E. D. Spoerke et al.