I’ve known some people who had the preconceived idea, that in general, batteries would generate – or produce – a voltage of 1.5V, and whose main distinction was either between battery formats, or brand-names. This idea would imply that those people had no exposure to The series of electrode potentials which all elements and most compounds have, relative to hydrogen. Different electrode potentials lead to different battery potentials, as long as the latter are taken separately, for the positive and the negative electrode.
But additionally, Engineers had an early goal, of supplying 1.5V batteries, which could act as direct drop-in replacements, for Carbon-Zinc batteries, where the carbon or manganese-oxide powder actually act as a hydrogen electrode, but which would provide much higher amounts of charge, before becoming passive. And so somewhere along the way, they also designed 1.5V lithium-based batteries, that could not be recharged. Considering that lithium itself has an electrode potential of about -3V, the only way in which this could be realized, was in a composition being chosen for the positive electrode, which offset some of those 3V, against the efficient generation of electricity.
In other words, these batteries wasted some of the energy which lithium offers as a fuel, just to arrive at less than 3V battery voltage. And closer examination of that subject should reveal, that some choice of metal was likely, as a positive electrode. But this is easily doable, as many metals will absorb the element lithium, yet have some electrode potential of their own, near -1.5V . Either Zinc or Manganese in their metallic form should work.