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Germany has created batteries from rotten apples
Last reviewed: 02.07.2025
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Spoiled apples as a source of energy may seem like an absurd idea at first glance, but a group of researchers at the Karlsruhe Institute of Technology have decided to use this material to create cheap, high-performance sodium-ion batteries. The technology proposed by the German researchers is probably the greenest of all that exists today.
The invention can be used as a simple and affordable energy storage device, and with the development of technology, sodium-ion batteries based on rotten apples will be able to compete with lithium-ion batteries, which are widely used today in portable electronic devices and small electric vehicles.
Strict culling (by size, colour and other external defects) results in a rather large amount of unsuitable fruits remaining after the apple harvest, which, as a perishable product, are almost immediately sent for disposal. By the way, in Europe the problem of waste after harvesting is quite acute, some fruits and vegetables rot quite quickly and cannot even be used as animal feed, small private companies offer various ways to solve the problem, but their efforts are usually insufficient.
Researchers from the Karlsruhe Institute Stefano Passerini and Daniel Buchholz have proposed an unusual and useful use for spoiled apples. The dried fruit is 95% carbon, from which "hyperdense carbon" is obtained - an electrode with low cost and high productivity.
Experts were able to create an anode based on “apple carbon” that has a specific capacity of 230 mAh/g and retains its original properties even after 1000 battery charge and discharge cycles.
Scientists noted that the percentage of capacity that is lost after the battery is discharged and charged (the so-called Coulomb efficiency of the electrodes) was established at a fairly high level – 99.1%.
During the work, the scientists also created a cathode for the “apple” battery that is environmentally friendly and highly productive – a multi-layer oxide made it possible to obtain a material that can be compared to lithium-ion cathodes, but with several differences – charge retention of 90.2% after more than 500 cycles and an efficiency factor of more than 99.9%.
Lithium-ion batteries can store a large amount of energy, but they also contain materials that are dangerous to life and health, such as cobalt, and the cost of such energy storage devices is quite high.
Sodium-ion batteries are cheaper and are made from simple and affordable materials, but their performance is in no way inferior to lithium-ion batteries.
According to Professor Passerini, sodium-ion batteries are only 20% less efficient than lithium-ion batteries, but the new development practically equals the capabilities of the batteries.
Today, despite their low cost, sodium-ion batteries are not very common, but scientists are confident that their development, due to their availability and low cost, will become the most widely used anode material.
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