Physics / mechanism
Sodium-ion batteries (SIBs) use Na⁺ intercalation between anode and cathode, analogous to lithium-ion but with Na⁺ (ionic radius 1.02 Å vs Li⁺ 0.76 Å), requiring wider-lattice host materials. Cathodes: layered oxides (NaMnO₂ variants), Prussian blue analogues (PBAs), or polyanionic frameworks (NASICON). Anodes: hard carbon dominates (~300 mAh/g practical). No lithium, no cobalt, no nickel required. Current SoA: ~140–160 Wh/kg cell-level (CATL’s first-gen), cycle life 3,000–4,000 cycles at 80% DoD, C-rate capability often superior to LFP. Cost target sub-$50/kWh at scale is credible given abundant precursors. Fast-charge kinetics advantage stems from weaker Na⁺ solvation energy.
Competitive landscape
SIBs compete directly with LFP (lithium iron phosphate) in stationary storage and low-cost EV segments. NMC/NCA remain dominant for energy-dense mobility. Adjacent electrochemical approaches include potassium-ion (cheaper still, worse kinetics), zinc-ion (aqueous, safer, lower energy density), and flow batteries (vanadium, iron-air) for long-duration storage.
Companies using
Connected ideas
Sources
Frontier (open questions)
- To be added.