Sustainable and safe energy sources combined with cost effectiveness are major goals for society when considering the current scenario of mass production of portable and Internet of Things (IoT) devices along with the huge amount of inevitable e-waste. The conceptual design of a selfpowered "eco-energy" smart card based on paper promotes green and clean energy, which will bring the zero e-waste challenge one step closer to fruition. A commercial raw filter paper is modified through a fast in situ functionalization method, resulting in a conductive cellulose fiber/polyaniline composite, which is then applied as an energy harvester based on a mechano-responsive charge transfer mechanism through a metal/conducting polymer interface. Different electrodes are studied to optimize charge transfer based on contact energy level differences. The highest power density and current density obtained from such a paper-based "eco-energy" smart card device are 1.75 W m −2 and 33.5 mA m −2 respectively. This self-powered smart energy card is also able to light up several commercial light-emitting diodes, power on electronic devices, and charge capacitors.

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