"Last tree in the LAB" (by Yuni Lim www.yuniworks.com)
As we hail ourselves as masters of Science and engineering, it can be seen time and time again that humans still have much to learn from the simplest of structures that surround us. This time, that simple yet complex and highly capable structure is the tree, and the lesson to be learned is sustainable, renewable, electrical energy storage.
Professor of biomolecular and organic electronics, OlleInganas from Linkoping University, is proposing to use a tree byproduct product called lignin, to produce highly efficient cathodes for batteries.
Inganas discovered this possible use by studying the process of photosynthesis. Electrochemically active molecules called quinones are the ones responsible for transporting solar-charged electrons. Quinones are composed of benzene rings made of six carbon atoms. These structures can be found abundantly in the lignin byproduct of paper pulp. Lignin itself comprises 20-30% of the biomass of a tree so it is highly renewable.
Conventionally, non-renewable metals are used as cathodes in rechargeable batteries. Turning the page beyond this convention, Inganas and his team have been able to make a cathode out of a 0.5 micron film of lignin derived from brown liquor, which is a waste material produced when making paper pulp.
Advancements in the efficiency of organic solar cells could be used in concert with these tree-derived batteries and scaled to industrial scales all while being efficient, sustainable, renewable, resourceful and cheap. Professor Inganas put it simply when speaking of electrical energy storage, “Nature solved the problem long ago."