I thought if I combined 2 galvanic cells so that the middle one serves as the anode for one cell while being a cathode for the other due to difference in standard reduction potential and the middle one get reduced from one cell and get oxidized at the other creating endless current. So is my "idea" right?
Yeah..your idea is technically right as long as you have the resources to keep up both the anode and cathode of the two cells which are not at the common side....ie if ure using a daniel cell and a Cu/Cu+||Ag+/Ag cell...as long as you suppliment Ag+ and Zn to the cell...youll have the cell up and running....
P.S:I wouldnt regard it as practical though