Sodium-Ion Battery: Hard-Carbon Anode Voltage Curve

Sodium-ion cells swap graphite for hard carbon at the negative electrode, and that single substitution reshapes the whole discharge curve: hard carbon's Na⁺ storage mechanism produces a sloping region at moderate charge followed by a long, nearly flat, near-zero-volt plateau as the electrode approaches full sodiation. This simulator renders a real 3D sodium-ion cell — a hard-carbon anode block, a layered-oxide cathode block, and a population of Na⁺ ions that visibly shuttle between them — driven by a two-electrode open-circuit-voltage model with an IR-drop term for current and an exponential cycle-life fade term for aging, so you can watch C-rate and capacity retention bend the terminal voltage away from the ideal curve in real time.