Different materials for cathode and annode in the same DC supply?
The Lithium Ion battery cathode is Aluminum coated with LiMn2O4, the anode is Copper coated with graphite. Here is a link to a mfgr's anodes.

The aluminum and copper are brought outside of the cell for connection. The dissimilar metals can be managed by cladding the aluminum. From the pics of the dreamliner cells, it looks like a triangular intermediate link is connected by rivets to two posts going into the cell. 

I am gonna guess that the diagram is not exactly correct, and guess that those triangular links are copper, so the interconnect is not across dissimilar metals.