I dug up in the archives a reference to Marco Berti, of ItLUG, battery layout in the old NXT, which featured this mix of 8 x 1.2V NiCd accumulators, for a total of 9.6V and much more current than standard alkaline cells.

There is also a reference to this battery combination is the book “Building Robots with Lego Mindstorms” by Mario Ferrari.