Lithium-ion batteries have established themselves as essential energy storage devices in modern life, from smartphones to electric vehicles. However, issues such as explosion risks, resource depletion, and environmental pollution remain unresolved. Researchers around the world are looking for answers in nature, developing battery electrodes using components from fruit scents and peels.
◇Synthesis of cathodes using amino acids and vitamins
On the 23rd (local time), a research team at Texas A&M University announced in the Proceedings of the National Academy of Sciences (PNAS) that they synthesized polymers for use as cathode materials by utilizing natural substances obtained from plants and animals.
A battery is fundamentally composed of two electrodes, the anode and the cathode, separated by a separator. Ions from the cathode move to the anode through a liquid electrolyte, generating current by moving electrons in the opposite direction.
The main component of the polymer material used for electrodes is a polypeptide backbone composed of the natural amino acid L-glutamic acid. Vitamin B2 (riboflavin) is combined on top of it. Riboflavin plays a crucial role in receiving and transferring electrons to store energy, assisting in the charging and discharging of the battery and enhancing its performance.
Karen Wooley, a professor at Texas A&M University, said, "This material could become a component of next-generation batteries with sufficient electrical storage capacity without placing a burden on the environment."
The organic polymer used to create the electrodes is designed for degradation, making it easy to recycle later. Its toxicity is also low. When tested on rat cells, it exhibited almost no toxicity. In the future, it could be applied to wearable or implantable electronic devices.
◇Eco-friendly battery materials made from citrus scent components
There is research that created radical polymer electrodes using a terpene (β-myrcene) extracted from plants. Radicals are unpaired electrons or atoms. As a highly transparent and flexible radical conductive polymer, it is attracting attention as a next-generation material. However, the backbone of such polymers is mostly made from chemical substances derived from petroleum.
In January 2023, a joint research team from Purdue University and Ohio University created eco-friendly polymers from terpenes, aromatic components found in citrus or herbaceous plants, and attached stable radicals that carry electric charge and ions to develop a new material that effectively transmits both.
The researchers explained, "Radical polymers can be produced easily and are suitable materials for optimizing battery performance, as their thermal and electrical properties can be controlled," noting that they demonstrated that battery materials made from plant-derived materials can be used as electrodes or electrolytes.
◇Batteries made from fruit peels achieving performance and expense
Cellulose-based batteries are technologies that apply cellulose extracted from plant resources such as citrus peels or cotton pulp to various battery components, including electrodes, electrolytes, and separators.
On the 1st of January, a research team from the Harbin Institute of Technology and Northeast Electric Power University utilized cellulose pieces obtained from grapefruit peels as electrodes and electrolytes to implement a flexible, mechanically strong zinc-ion battery.
The electrodes of the battery are structured like a sandwich. Carbon nanotubes are embedded between thin layers of cellulose, allowing electric and ionic transport to occur rapidly. Carbon nanotubes are fine bundles of carbon atoms connected in a hexagonal honeycomb structure, which have high electrical conductivity. The electrolyte is made in a moisture-rich gel form, facilitating the movement of zinc ions.
In April, a research team from Wuhan University of Technology used a cellulose-carbon nanotube composite to create a lightweight, high-strength cellulose composite film as the current collector for lithium-ion batteries. The current collector is a component that acts as a pathway for moving electrons within the battery.
Replacing the conventional aluminum and copper commercial current collectors with a cellulose composite film reduced the proportion of the battery's weight attributed to the current collector to 6.23%, while the energy storage per weight of the entire battery increased by about 41%. The production expense of the current collector was reduced by more than half. Batteries utilizing this material maintained 99.4% performance even after 500 charge and discharge cycles.
The researchers noted, "Cellulose composite films can be produced on a large scale in factories, making them immediately applicable industrially," and stated that it could be a new solution for creating lighter, cheaper, and longer-lasting batteries.
References
Proceedings of the National Academy of Sciences (2025), DOI: https://doi.org/10.1073/pnas.2509325122
Journal of Colloid and Interface Science (2025), DOI: https://doi.org/10.1016/j.jcis.2024.09.036
Communications Materials (2025), DOI: https://doi.org/10.1038/s43246-025-00802-6