The resulting anode material is said to have twice the capacity and a longer life cycle than conventional materials used in Li-ion rechargeable batteries.
However, pure silicon expands three to four times its volume during the process in which Li ion is incorporated into it; as a result, pure silicon anode materials are prone to crack as a large amount of stress is applied to them during repeated charge-discharge cycles.
To counter this, the research group created nanostructured Si-metal composites, using one-dimensional germanium nanowires on metal substrates as a base material layer. The formed nanostructured material has numerous cavities inside clusters of nanoparticles. These cavities act as buffer space to absorb stress generated by the expansion of pure silicon, and by regulating the composition of Si and metal elements in the Si-based nanostructure.
