Samsung researchers reportedly developed materials that can be used to double the capacity of Li-ion batteries. The key to the more efficient batteries is a new graphene-based cathode material. It is a new silicon cathode material "coded with high-crystalline graphene". As deployed in its lithium-ion batteries the new cathodes produce cells "with twice as much capacity as ordinary lithium-ion batteries," according to various reports.
This research presents a dramatic improvement of the capacity of lithium-ion batteries by applying a new synthesis method of high-crystalline graphene to a high-capacity silicon cathode. Samsung's team used silicon cathodes instead of graphite ones; this is not a novel approach, since many previous studies have also used it. The challenge, however, is that the silicon can expand or contract during the battery charging and discharging cycles. Samsung addressed this issue by creating a process to grow graphene cells directly on the silicon in layers that can adjust to allow for the silicon's expansion: "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 700âWhâl-1 at first and 200th cycle, respectively, 1.8 and 1.5 times higher than those of current commercial lithium-ion batteries."