As demand for electric vehicles soars, scientists are searching for materials to make sustainable batteries. Lignin, the stuff that makes trees woody, is shaping up to be a strong contender.  …Stora Enso, in Finland, describes itself as “one of the largest private forest owners in the world”. As such, it has a lot of trees, which it uses to make wood products, paper and packaging, for example. Now it wants to make batteries as well – electric vehicle batteries that charge up in as little as eight minutes.  The company hired engineers to look into the possibility of using lignin, a polymer found in trees. Around 30% of a tree is lignin, depending on the species – the rest is largely cellulose. …Lignin, a polymer, contains carbon. And carbon makes a great material for a vital component in batteries called the anode.