Researchers from the University of California Riverside have developed a paper-like material for lithium-ion batteries. The new material has the potential to boost the amount of energy that can be delivered per unit weight of the battery. The material is composed of sponge-like silicon nanofibers. The nanofibers were produced using electrospinning; 20,000 to 40,000 volts are applied between a rotating drum and a nozzle, which emits a solution composed mainly of tetraethyl orthosilicate. The nanofibers are then exposed to magnesium vapor to produce the sponge-like silicon fiber structure. The problem with silicon is that it undergoes significant volume expansion, which can degrade the battery. The silicon nanofiber structure circumvents this issue and allows the battery to be cycled hundreds of times without significant degradation. As a next step, the researchers will incorporate the silicon nanofibers into a pouch-cell-format lithium-ion battery, which is a larger scale battery format.