I took apart an old lead-acid car battery and realised then, that there are almost equal parts of lead and lead dioxide.

Already having saved and distilled the acid, I started to think there was a lot more effort involved giving all the safety steps and time than buying the items separately.

Decomposition of lead(IV) oxide at different temperatures forms different types of oxides. At around $$\pu{600 ^\circ C}$$, lead(II) oxide forms. Wikipedia adopts the scheme of lead(IV) oxide decomposition in air summarized by White and Roy [1]:

$$\ce{PbO2 ->[\pu{293 ^\circ C}] Pb12O19 ->[\pu{351 ^\circ C}] Pb12O17 ->[\pu{375 ^\circ C}] Pb3O4 ->[\pu{605 ^\circ C}] PbO}$$

You can then reduce lead(II) oxide to lead using carbon or carbon monoxide at around $$\pu{1200 ^\circ C}$$. The effect of dissolved inorganic carbon is discussed by Wang et al. [2]

\begin{align} \ce{PbO + CO &->[\pu{1200 ^\circ C}] Pb + CO2}\\ \ce{2 PbO + C &->[\Delta] 2 Pb + CO2} \end{align}

Note that lead(II) oxide can also decompose to release toxic fumes of lead which can be harmful and also doesn't serves your purpose of getting solid lead.

### References

1. White, W. B.; Roy, R. Phase Relations in the System Lead-Oxygen. J American Ceramic Society 1964, 47 (5), 242–249. DOI: 10.1111/j.1151-2916.1964.tb14404.x.
2. Wang, Y.; Xie, Y.; Li, W.; Wang, Z.; Giammar, D. E. Formation of Lead(IV) Oxides from Lead(II) Compounds. Environ. Sci. Technol. 2010, 44 (23), 8950–8956. DOI: 10.1021/es102318z.

Lead dioxide can be heated to 600 °C and it will thermally decompose into PbO and O2. This likely creates lead fumes but this may be one way to accomplish the task.

Optionally, you could dissolve the lead dioxide in acid then reduce it from a salt.

Welcome to this community, but please use care. Be careful with the DIY approach to doing chemistry when it comes to high temperatures or somewhat dangerous materials such as lead.

• Thank you for your reply, I wear acid rated PPE, face shields and take extra precautions with a bicarb wash. Also outside. Using a acid to dissolve it to a salt, this sounds more dangerous then creating a old style coke forge to take it up to 1200 then collect the lead from the bottom once cooled. Then refine it. – jonboy79 Jul 27 at 10:13