Outdoor Experiment Mixing Lithium and Alkaline Extending Battery Life in 4 x AA Battery Bank

What happens when you mix Lithium and Alkaline in the same battery bank? What happens in colder temperatures? The voltage of Lithium is higher so I wanted to mix to achieve a lower voltage. Lithium seems to perform better in cold environments.

[@GeorgeHafiz]

Why not just use four lithium batteries? Is it because most devices expect 1.5 V per cell and the lithium cells being at 1.8 V will damage them? Could it be a straightforward modification to make such devices tolerate this higher voltage and reduce the time between battery swaps even further?