Sodium-ion batteries operate analogously to lithium-ion batteries, with both chemistries relying on the intercalation of ions between host structures. In addition, sodium based cell construction is almost identical with those of the commercially widespread lithium-ion battery types. However, sodium-ion batteries are characterised by several fundamental differences with lithium-ion, bringing both advantages and disadvantages:
- Environmental abundance: Sodium is over 1000 times more abundant than lithium and more evenly distributed worldwide.
- Safety: Sodium-ion cells can be discharged to 0V for transport, avoiding thermal run-away hazards which have plagued lithium-ion batteries.
- Low cost: Sodium precursors (such as Na2CO3) are far cheaper than the equivalent lithium compounds.
- Three major families of materials for cathode chemistry options:
- layered transition metal oxides
- polyanionic compounds
- prussian blue analogs
- Cathode materials can be synthesized from more sustainable transition metals such as Fe, Cu or Mn.
- Sodium-ion cells have lower energy densities than lithium-ion. This is due to sodium being significantly heavier and larger than lithium, as well as Na+/Na having a higher reduction potential than Li+/Li.
- Sodium-ion technology is not as well established as lithium-ion.
Many of the battery components in both sodium-ion and lithium-ion batteries are similar due to the similarities of the two technologies. This post provides a high-level overview for the constituent cell parts in Sodium-ion batteries.
- An energy density of 100 to 160 Wh/kg and 290Wh/L at cell level.
- A voltage range of 1.5 to 4.3V. Note that cells can be discharged down to 0V and shipped at 0V, increasing safety during shipping.
- 20-30% lower cell BOM cost than LFP.
- A wider operating temperature than lithium-ion cells (-20°C to +60°C).
- Typical Energy efficiency 92% at C/5.
- Emerging battery technology – promising cost, safety, sustainability, and performance advantages over current commercialised lithium-ion batteries1,2.
- widely available
- inexpensive raw materials
- rapidly scalable technology
- meeting global demand for carbon-neutral energy storage solutions3,4.
- Adding metals would increase the overall energy density, but results in volumetric changes leading to failure.
- Over-voltage Charging
- Presence of Hydrogen
- causes irreversible degradation of α-NaMnO2 when used as the cathode in Na-ion batteries .
- Defects in the Cathode Atomic Structure
- these form during the steps involved in synthesizing the cathode material. These defects eventually lead to a structural earthquake in the cathode, resulting in catastrophic performance decline during battery cycling .
This low cot battery technology is approaching fast with lots of announcements.
Achieving 120Wh/kg at pack level.
- Zhen Zhu, Hartwin Peelaers, Chris G. Van de Walle, Supporting Information: Hydrogen-induced degradation of NaMnO2, Chem. Mater. 2019, 31, 14, 5224–5228, June 21, 2019
- Xu, GL., Liu, X., Zhou, X. et al. Native lattice strain induced structural earthquake in sodium layered oxide cathodes. Nat Commun 13, 436 doi: 10.1038/s41467-022-28052-x
- Behrooz Mosallanejad et al, Cycling degradation and safety issues in sodium-ion batteries: Promises of electrolyte additives, Journal of Electroanalytical Chemistry, Volume 895, 15 August 2021, 115505
- Comprehensive Inorganic Chemistry III, Reference Work • Third Edition • 2023