Biobatteries: Light and digestible

Biobatteries:

Light and digestible

A comment from Frauke Zbikowski

Sep 30, 2026, 3:34 p.m

They already work in pig stomachs: biodegradable batteries.

Biodegradable batteries are intended to make medical devices safer in the body. Now there are even such power sources that do not immediately dissolve in the pig's stomach. But you shouldn't eat too many of them.

Batteries made from biomaterial are very popular, but so far they have often had a catch for medical purposes: either they did not provide enough power or they dissolved too quickly. Mostly both. If the power sources are supposed to power a pacemaker, for example, it is not enough that they are non-toxic and gentle on the tissue - even if the performance is right. What is crucial is that the batteries must not dissolve within a few hours and be absorbed without leaving any residue, like a model made of paper, vitamin B2 and algae that entered the world of batteries a few years ago.

In the case of a biobattery made from mushrooms, which scientists presented as non-toxic last year, it is not clear whether it is actually wholesome. The velvety tramete, a white rot fungus that makes up one of the electrodes, is very easily degradable in the environment. But it is not an edible mushroom. Then why not stick with the proven toxic and non-degradable batteries and encapsulate them properly so that they cannot dissolve at all, especially not in body fluids?

A battery that is biodegradable is simply safer in the human body, write scientists from the Massachusetts Institute of Technology and Harvard Medical School in the journal “Nature Chemical Engineering.” We have therefore developed a battery that can withstand aggressive gastric juices for the duration of medical diagnostics or therapy. If it bursts, it does not create sharp edges or release toxins. It also doesn't get overly hot if something goes wrong. Instead, it provided the necessary voltage for small electronic devices for days in the stomach - tested in the digestive organ of living pigs. But the system is far from perfect.

There's a catch: the cathode is made of molybdenum trioxide, and that's carcinogenic. Well, the amounts in the battery are extremely small and remain below the tolerable intake level. But the electronic device that is connected to the easily digestible battery contains a completely conventional circuit board - and it is still far from being biodegradable.