GelBat: An Edible Gelatin-Based Battery

Abstract

The development of green batteries has implications for many fields including sustainable robotics and edible electronics. Here we present GelBat, a biodegradable, digestible and rechargeable battery constructed from gelatin and activated carbon. The device utilises the water splitting reaction to produce a simple, sustainable Bacon fuel cell which can produce an output voltage of over 1V for 10 minutes, depending on the load resistance, with 10 minutes of charging and whose only byproduct is water. Electrochemical impedance spectroscopy, cyclic voltammetry and self discharge tests are carried out to characterize the behaviour of the battery. The system does not lose any efficiency with repeated recharging cycles and can be completely dissolved in a simulated gastric fluid within 20 minutes. The simplicity of this design combined with the bioresorbable materials demonstrates the potential of this work to help advance robotic research towards more sustainable untethered autonomous systems and edible robots.

A Sprayable Electrically Conductive Edible Coating for Piezoresistive Strain Sensing

“…However, ionic conductors [ 27 − 33 ] rely on hydration and the charge transport mechanism involves ions migration instead of electrons flow. Thus, they are influenced by environmental conditions and are not compatible with recently developed edible power supplies [ 34,35 ] as they typically cannot be easily operated in a direct current regime. Electronic conduction, where current is due to the movement of electrons, as in a common metal wire, is instead suitable for direct current operation.…”

“…[ 24,39 − 44 ] AC has been used in combination with polydimethylsiloxane (PDMS), [ 39,40 ] concrete, [ 42 ] foams, [ 43 ] and hydrogels [ 45 ] to produce strain sensors for wearable and structural health monitoring applications. Also, a large variety of edible electronics components leveraging AC have been already implemented (e.g., electrochemical sensors, [ 46 ] supercapacitors, [ 47 ] batteries, [ 34,35 ] tilt sensors, [ 18 ] triboelectric generators, [ 41 ] electrodes, [ 24 ] pressure sensors [ 13 ] ). However, a food‐based strain sensor employing AC as the electronic conductor suitable to be operated in a direct current regime and therefore compatible with edible batteries [ 34,35 ] has not been documented yet.…”

“…The sensor presented here can operate with direct current and is therefore compatible with edible energy sources. [ 34,35 ] The sensor properties are validated by integrating it with an edible gripper [ 50 ] and an edible battery, [ 34 ] resulting in a sensorized edible gripper.…”