Since 2014, rechargeable lithium-ion batteries used to store green electricity, among other things, are being superseded by a new generation of more efficient and eco-friendly batteries made from bio-based materials. In this context, Oregon State University chemists discovered a chemical component that will revolutionize the industry of electric batteries. Before outlining their study, which was published in the Journal of the American Chemical Society ACS Energy Letters, here is a brief overview of the latest technologies in electrical energy storage.
Lithium Li-ion Batteries
With the proliferation of portable devices, lithium Li-ion batteries, created in 1991 by Sony Energitech, are the most widely used. They provide very significant benefits for the operation and autonomy of the objects they power:
- They recharge quickly and discharge slowly;
- They have a very low self-discharge (10%);
- They can be scaled for different applications. Lithium Li-ion batteries are used in tablets, mobile phones, electric vehicles and even space probes.
Yet lithium, despite its light weight and high energy density (250-620 W·h/L), has drawbacks with regard to its carbon footprint, toxicity, high cost and scarcity, prompting the search for more eco-friendly materials with less risk of toxicity and more recycling possibilities.
Ryden Batteries: An Environmentally Responsible Solution for the Automobile Industry
Ryden batteries, developed in 2014 by the U.S.-Japan start-up Power Japan Plus, and Kyushu University (Japan), are now considered to be the most effective and most environmentally responsible electrical energy storage devices on the market today. Unlike lithium Li-ion batteries, they are 100% eco-friendly because they do not use rare or heavy metals, are made from a recyclable material and are less expensive to produce. In fact, their anodes and cathodes are made with Carbon Complex, which is derived from cotton, coffee beans or bamboo.
The Ryden technology was tested by the Japanese Taisan Team. They developed batteries that, in August 2014, powered an electric kart. Their tests validated the functional performance of the Ryden “double carbon” cells: unlike lithium batteries, these do not overheat during a race. The driver no longer has to stop when a certain speed or distance is reached. In addition to its lightness, the Ryden battery does not require a complex and bulky cooling system.
Furthermore, under the Cradle to Cradle environmental ethics concept advocated by American architect William McDonough, a product or service is truly 100% green when it reuses matter generated by the human material environment to recreate the same product or create a different one. The discovery made by Oregon State University (OSU) scientists is in line with this concept, as it ensures the capture of harmful emissions and their use in battery manufacturing. The challenges of rerouting harmful emissions into the ecosystem are presented in the book entitled Cradle to Cradle: Remaking the Way We Make Things (2003), by William McDonough and Michael Braungart.
Coronene in the Chemical Composition of Batteries of the Future
A group of researchers (Ismael A. Rodríguez-Pérez, Zelang Jian, Pieter K. Waldenmaier, Joseph W. Palmisano, Raghu Subash Chandrabose, Xingfeng Wang, Michael M. Lerner, Rich G. Carter and Xiulei Ji) of the OSU Chemistry Department discovered that with polycyclic aromatic hydrocarbons (PAHs), much cheaper and more reliable batteries can now be manufactured. PAH compounds are pollutants that can be found everywhere. Recycling them produces more resistant batteries and decontaminates the environment. PAHs are produced by combustion and spread in the main environmental areas, namely water, soil and air. In 1976, they were classified by the U.S. Environmental Protection Agency among the list of priority pollutants because of their high toxicity.
The battery developed by the OSU group will consist of a carbon anode and a PAH-based cathode. In their article entitled “A Hydrocarbon Cathode for Dual-Ion Batteries”, the researchers took a particular interest in one type of PAH named coronene. After testing coronene in a safe and solid crystalline form, PAH was found to be the most efficient compound because it has a good ion storage capacity while maintaining structural and chemical stability: desirable features for batteries designed to store wind and solar energy. Although, from this perspective, graphite has the same advantages as coronene, Xiulei Ji showed that it is incompatible with the non-aqueous electrolyte used to provide electrical conductivity between the anode and the cathode. Coronene does not present this problem and, consequently, does not entail the support and maintenance costs of a stationary battery system.
Studies on the formation of new stars in the Statue of Liberty Nebula have detected the presence of PAHs and have led to the assumption that they were also present in the stellar environment where the Sun originated. From stars to batteries, PAHs come from the initial energy and return to it over and over, or from cradle to cradle!