Flexible iontronics based on 2D nanofluidic material.

Iontronics focuses on the interactions between electrons and ions, playing essential roles in most processes across physics, chemistry and life science. Osmotic power source as an example of iontronics, could transform ion gradient into electrical energy, however, it generates low power, sensitive to humidity and can't operate under freezing point. Herein, based on 2D nanofluidic graphene oxide material, we demonstrate an ultrathin (∼10 µm) osmotic power source with voltage of 1.5 V, volumetric specific energy density of 6 mWh cm -3 and power density of 28 mW cm -3 , achieving the highest values so far. Coupled with triboelectric nanogenerator, it could form a self-charged conformable triboiontronic device. Furthermore, the 3D aerogel scales up areal power density up to 1.3 mW cm -2 purely from ion gradient based on nanoconfined enhancement from graphene oxide that can operate under -40 °C and overcome humidity limitations, enabling to power the future implantable electronics in human-machine interface.