FIG. 4 is a side view of another embodiment of a stacked-die processor 424 with a first die 432, a second die 434, and a third die 444. In some embodiments, a first microfluidic volume 436 is located between the first die 432 and the second die 434, and a second microfluidic volume 446 is located between second die 434 and the third die 444. In some embodiments, a first electrochemical fluid 408 is located in the first microfluidic volume 436 and a second electrochemical fluid 410 is located in the second microfluidic volume 446. The first microfluidic volume 436 and the second microfluidic volume 446 form at least part of an electrochemical chamber 404 that is divided by the second die 434 and an ion-transfer membrane 406. In some embodiments, a first electrode 420 and a second electrode 422 contacting the first electrochemical fluid 408 and the second electrochemical fluid 410, respectively, allows the electrochemical chamber 404 to provide electrical power to at least the second die 434. In some embodiments, one or more TSVs 448 located in heat transfer structures 440 or other structures between the second die 434 and the first die 432 and/or third die 444 can transmit electrical power from the electrodes 420, 422 to different parts of the processor 424.
