A nanofluidic chemoelectrical generator with enhanced energy harvesting by ion-electron Coulomb drag

Abstract A sufficiently high current output of nano energy harvesting devices is highly desired in practical applications, while still a challenge. Theoretical evidence has demonstrated that Coulomb drag based on the ion-electron coupling interaction, can amplify current in nanofluidic energy generation systems, resulting in enhanced energy harvesting. However, experimental validation of this concept is still lacking. Here we develop a nanofluidic chemoelectrical generator (NCEG) consisting of a carbon nanotube membrane (CNTM) sandwiched between metal electrodes, in which spontaneous redox reactions between the metal and oxygen in electrolyte solution enable movement of ions within the carbon nanotubes. Through Coulomb drag effect between moving ions in these nanotubes and electrons within the CNTM, an amplificated current of 1.2 mA·cm-2 is generated, which is 15.6 times higher than that collected without a CNTM. Meanwhile, one single NCEG unit can produce a high voltage of ~0.8 V and exhibit a linear scalable performance up to tens of volts. Different from the other Coulomb drag systems that need additional energy input, the NCEG with enhanced energy harvesting realizes the ion-electron coupling by its own redox reactions potential, which provides a possibility to drive multiple electronic devices for practical application.