Low-bias voltage intrusion-extrusion eletric generator

The present invention refers to a durable and robust intrusion/extrusion generator cell, to an energy storage and/or delivery system comprising said cell, to a method of storing and/or delivering electricity comprising said cell, and to the use of the cell and the system to store or deliver electricity. The asymmetric configuration of the porous material inside the generator cell (being much closer to one of the electrodes than to the other one) allows generating electricity with low or even zero bias voltage, thus, preventing the degradation of the porous material.