Batteries
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Standard potentials in aqueous solution at 298K
| Reaction | Eo (V) |
|---|---|
| Li+ + e– → Li | -3.10 |
| Na+ + e– → Na | -2.71 |
| Mg2+ + 2e– → Mg | -2.36 |
| ½H2 + e– → H– | -2.25 |
| Mn2+ + 2e– → Mn | -1.18 |
| MnO2 + 2H2O + 4e– → Mn + 4OH– | -0.98 |
| 2H2O + 2e– → H2 + 2OH– | -0.83 |
| Cd(OH)2 + 2e– → Cd + 2OH– | -0.82 |
| Zn2+ + 2e– → Zn | -0.76 |
| Ni(OH)2 + 2e– → Ni + 2OH– | -0.72 |
| Fe2+ + 2e– → Fe | -0.44 |
| Cd2+ + 2e– → Cd | -0.40 |
| PbSO4 + 2e– → Pb + SO42– | -0.35 |
| Ni2+ + 2e–→ Ni | -0.26 |
| MnO2 + 2H2O + 4e– → Mn(OH)2 + 2OH– | -0.05 |
| 2H+ + 2e– → H2 | 0.00 |
| Cu2+ + e– → Cu+ | +0.16 |
| Ag2O + H2O + 2e– → 2Ag + 2OH– | +0.34 |
| Cu2+ + 2e– → Cu | +0.34 |
| O2 + 2H2O + 4e– → 4OH– | +0.40 |
| 2NiOOH + 2H2O + 2e– → 2Ni(OH)2 + 2OH– | +0.48 |
| NiO2 + 2H2O + 2e– → Ni(OH)2 + 2OH– | +0.49 |
| MnO42– + 2H2O + 2e– → MnO2 + 4OH– | +0.62 |
| 2AgO + H2O + 2e– → Ag2O + 2OH– | +0.64 |
| Fe3+ + e– → Fe2+ | +0.77 |
| Hg2+ + 2e– → Hg | +0.80 |
| Ag+ + e– → Ag | +0.80 |
| 2Hg2+ + 2e– → Hg+ | +0.91 |
| O2 + 4H+ + 4e– → 2H2O | +1.23 |
| ZnO + H2O + 2e– → Zn + 2OH– | +1.26 |
| Cl2 + 2e– → 2Cl– | +1.36 |
| PbO2 + 4H+ + 2e– → Pb2+ + 2H2O | +1.47 |
| PbO2 + SO42– + 4H+ + 2e– → PbSO4 + 2H2O | +1.70 |
| F2 + 2e– → 2F– | +2.87 |
Cells using aqueous electrolytes are limited to under 2 V as water is decomposed at higher voltages. Thus Li batteries available in the 2.7 to 4 V use non-aqueous electrolyte. Typical non-aqueous electrolytes have higher impedance unless used as very thin films, eg lithium polymer battery or at higher temperatures.