Lead-Acid Battery: Standard Electrode Potential I'm making a lead-acid battery for an investigation. Since I only had sulfuric acid and lead electrodes, I decided to firstly run 2 lead electrodes through electrolysis in a sulfuric acid electrolyte. This would create the following half equations: 
$$\ce{4H+ + 4e- -&gt; 2H2}$$
$$\ce{Pb +2H2O-&gt;PbO2 +4H+ +4e-}$$
At this stage, I still need to perform some theoretical calculations of the required potential to run this electrolysis. Obviously, the standard reduction potential of the hydrogen ion is 0V. But I can't find the potential for the 2nd reaction. Could someone provide me with a source for it?
Your reactions are wrong. 

$$\ce{Pb(s) + HSO^−_4(aq) -&gt; PbSO4(s) + H+(aq) + 2e−}$$
$$\ce{PbO2(s) + HSO^−4(aq) + 3H+(aq) + 2e− -&gt; PbSO_4(s) + 2H2O(l)}$$

Lead acid batteries are fairly reversible, hence their use as rechargable batteries. Anything that produces a gas, like in your reduction reaction, is unlikely to be reversible.