More than half the weight and size of today’s batteries comes from supporting materials that contribute nothing to storing energy. Now researchers have demonstrated that genetically engineered viruses can assemble active battery materials into a compact, regular structure, to make an ultra-thin, transparent battery electrode that stores nearly three times as much energy as those in today’s lithium-ion batteries. It is the first step toward high-capacity, self-assembling batteries.
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One of the ways they have done this in the past is using a process called “directed evolution.” They combine collections of viruses with millions of random variations in a vial containing a piece of the material they want the virus to bind to. Some of the viruses happen to have proteins that bind to the material. Isolating these viruses is a simple process of washing off the piece of material –only those viruses bound to the material remain. These can then be allowed to reproduce. After a few rounds of binding and washing, only viruses with the highest affinity for the material remain.