| sodium ion | 1.58 | Typically, sodium ions are excluded and potassium ions are hoarded. | ||
| calcium ion | 0.59 | As with Aplysia, a key player in this process appears to be calcium ions. | ||
| chloride ion | 0.59 | The membrane starts off positively charged, and chloride ions can pass through easily. | ||
| potassium ion | 0.53 | Typically, sodium ions are excluded and potassium ions are hoarded. | ||
| bicarbonate ion | 0.33 | But the new research suggests bicarbonate ions also play a role. | ||
| lithium ion | 0.26 | For more sustained power, high-energy batteries, like nickel metal hydride and lithium ion, are better suited, Ms. Brush said. |