The key is almost finished, but it still needs a power source, which is why Kinzie sent C.I.D. to help you locate them. Fun Shaundi is sent along, too, but C.I.D. doesn't know the exact locations of the power sources and only the general area. As you search for them, there is a meter in the upper left of the screen that will fill up as you get closer to the power source.
The first one has some minor resistance, but when you get to the second one, you will find a force field surrounding it. So, you'll need to disable the generator powering the shield, then you can grab the battery. The third battery has some more generators, as well as more Zin, including a Marauder.
Disable the generators to get rid of the shield, but when you try to grab the battery, it explodes. Luckily, C.I.D. points out there's another one nearby, but when you find it, you see it is heavily fortified. Clear the area first, then go for the generators.
When the shield has been dropped, you find the battery is inside of a tank. Enter it and you now have three minutes to get it to Kinzie's warehouse, since the increase in power will make it explode in that time. There will be plenty of roadblocks in the way, but they shouldn't pose much of a problem for the tank. Once you get it back to the warehouse, the mission will be over.
