Achievement

Sean Wood investigates synthesizing new materials replacing graphite in anodes of lithium ion batteries. The use of other Group IV elements (silicon, germanium, tin, and lead) have much higher capacities that are structurally buffered from the inside against the huge expansion by substances like titania or alumina. There are two main scientific challenges resulting from the same fundamental problem: a massive 200-300% volumetric expansion during lithiation that results in a) rapid consumption of the battery’s lithium reserves by continual solid electrolyte interphase (SEI) formation and b) cycle life degradation by particle pulverization and electrical isolation. A directed engineering approach is used to create a protective layer on the outside of the particles with a built-in void space into which the particles can expand and contract without continually forming more SEI.