Even if you packed the powder into something, the problem is that the electricity would have to travel through many, many different grains of the metal powder. Each time it does that, it has to overcome the contact resistance of the metal and the resistance of whatever gap exists between each piece of metal. Add to that the fact that an oxide layer will start forming around the outside of each grain, creating even more resistance.
The end result is that electric currents do not travel through powders very well. Maybe powdered gold would work since it has a very low contact resistance and doesn't tarnish, but that's about it. Electricity much prefers going through solid metal.
"If tyranny and oppression come to this land, it will be in the guise of fighting a foreign enemy. The loss of Liberty at home is to be charged to the provisions against danger, real or imagined, from abroad." - James Madison