The methodology in summary form is to design and implement improvements to the nickel-iron battery.
Test-
1) Initial testing will involve ESR testing of an existing 10 Ah battery - standard wet type. as well as charge 1 discharge characteristics. charge acceptance and gassing during charging.
2) Design/construct then is for a gelled battery with new micro-porous battery separate material as discussed to replace the existing battery separator. and reducing the distance between the negative and positive plates. The initial tests in 1) will again be performed.
3) Similarly for a battery with carbon fibre construct added to the positive electrode (i.e. a half dipole super-capacitor) of 2) with the repeat of the tests.
Analyse all results of test in 1), 2) and 3).
This is your basic methodology, which needs more detail in the type of tests you will perform.