# Edible Pneumatic Battery for Sustained and Repeated Robot Actuation

## TL;DR

This paper introduces an edible battery system that uses a chemical reaction to power soft, edible robots capable of repeated motion.

## Contribution

The novelty lies in a fully edible pneumatic system that enables self-sustained and programmable actuation using food-grade materials.

## Key findings

- The system generates CO2 gas through the reaction of citric acid and sodium bicarbonate, enabling actuator deformation.
- The edible valve automatically releases gas when pressure reaches a threshold, allowing repetitive actuator motion.
- The design is scalable and programmable, demonstrated through a foot-triggered edible actuator mimicking prey behavior.

## Abstract

Energy production and storage represent challenges for biodegradable and edible technologies. Here, this study describes an edible energy storage and valve system designed to power pneumatically driven edible robots. The edible pneumatic battery exploits the acid‐base neutralization reaction of food‐grade reactants: under gravity, citric acid mixes with sodium bicarbonate powder to produce a steady release of carbon dioxide (CO2) gas. The generated gas pressure causes deformation of a connected edible pneumatic actuator. When the gas pressure reaches a threshold, an edible valve automatically releases the pressurized gas, which lets the actuator return to its resting state. The entire system, whose characteristics are consistent with model estimates, is fully edible and enables self‐sustained and repetitive bending motion of the edible actuator. This design is scalable in terms of sizes (30–50 mm diameter), operation time (20–650 s), and CO2 gas generation rate (0.1–1.4 × 10−3 mol s−1). Additionally, the actuator's motion can be programmed by modifying the orifice size or the fluidic resistance between the energy source, actuator, and valve. The system is validated by fabricating a fully edible system, and its application is showcased as a foot‐pressed triggered edible actuator that mimics prey behavior to attract predators.

This work presents an edible energy source and valve system to power soft, pneumatically driven edible robots. A chemical reaction between sodium bicarbonate and citric acid generates carbon dioxide gas, and a pressure‐triggered edible valve enables self‐repetitive motion of the edible actuator. The system is scalable, programmable, and demonstrated through a foot‐triggered actuator that potentially mimics prey to attract wildlife.