Sodium-Ion Battery Mechanism

The same rocking-chair principle as Li-ion, using abundant sodium and a hard carbon anode.

Step 1 / 3: Oxidation at Anode
e⁻ →e⁻ →External Load (Motor/Device)Anode (-)Hard Carbon (C)Electrolyte / SeparatorNa+ Permeable MembraneCathode (+)NaMO₂ OxideNa⁺ →

ANODE (OXIDATION)

NaₓC → C + x Na⁺ + x e⁻

Sodium stored in the hard carbon anode loses electrons (oxidation) and releases Na⁺ ions into the electrolyte.

CATHODE (REDUCTION)

Na₁₋ₓMO₂ + x Na⁺ + x e⁻ → NaMO₂

The layered oxide cathode is sodium-deficient, ready to receive incoming ions.

Sources: [45] Stevens et al. (2000) · [46] Hwang et al. (2017) · [47] Kim et al. (2012) · [58] Shannon et al. (1976)