The B-2 uses them.
have to check, but F-22 and F-35 may also use them.
The Nickel metal hydride batteries are used in the Toyota Prius after an attempt with the Li-ion doofers. Those nickel ones don't have the energy per weight/volume, but are less susceptible to burning up when over-charged. Less charging system protections and such requirements, so easier to engineer and employ.
Secondly, although the Li-ion ones dont have pure lithium ( highly reactive to water), they can still react to water once going into the thermal runaway stage. Damned hard to put the fire out.
We don't need to go back to lead-acid or even NI-Cad, but the new Li-ion doofers seem a little too risky for the applications in aircraft.