The research arm of Samsung Electronics announced on June 25 that it has developed a technology to make a silicon cathode material for coating high crystal graphene on a silicon surface to realize an energy density almost two times more than that of existing lithium batteries.
Existing lithium batteries, which were developed and commercialized by Sony in the 90’s, has been developed in a way of extending the capacity rather than increasing the life and density owing to limitations of material itself. The expansion of capacity has remained at best two times more than that of the first commercialized batteries.
Currently, the development of high-capacity battery materials has been mostly done in the United States. In particular, the research is active on silicon as a substitute material capable of raising the capacity more than 10 times that of the graphite currently used as an existing cathode material. There is, however, still the technological problem of the shortening the battery life by repeated charging and discharging.
The R&D center of Samsung Electronics has succeeded in developing a high-density and highly-durable cathode material by coating the strong and conductive graphene on the surface of the silicon to create a kind of protective layer around the silicon.
Samsung, which has been making efforts to improve battery capacity to differentiate itself from other global smartphone rivals, expects that it could bring a significant change to both mobile devices and the electronic car industry.
Industry watchers said the technology may need two or three years for commercialization.
Silicon is receiving discernable attention as an active material for next generation lithium-ion battery anodes because of its unparalleled gravimetric capacity. However, the large volume change of silicon over charge–discharge cycles weakens its competitiveness in the volumetric energy density and cycle life. Here we report direct graphene growth over silicon nanoparticles without silicon carbide formation. The graphene layers anchored onto the silicon surface accommodate the volume expansion of silicon via a sliding process between adjacent graphene layers. When paired with a commercial lithium cobalt oxide cathode, the silicon carbide-free graphene coating allows the full cell to reach volumetric energy densities of 972 and 700 Wh l−1 at first and 200th cycle, respectively, 1.8 and 1.5 times higher than those of current commercial lithium-ion batteries. This observation suggests that two-dimensional layered structure of graphene and its silicon carbide-free integration with silicon can serve as a prototype in advancing silicon anodes to commercially viable technology.