“Free of conductive additives, binders, commercial separators, and current collectors.” This claim, from researchers at Tsinghua University, China, reads like the health claims on my box of afternoon cereal. More seriously, it reads like the recipe for a highly simplified, low cost energy storage device, which they have produced using a TiO2-assisted UV reduction of sandwiched graphene components.
The sandwich structure consists of two active layers of reduced graphene oxide hybridised with TiO2, with a graphene oxide separator (rGO-TiO2/rGO/rGO-TiO2). In the completed device, the separator layer also acts as a reservoir for the electrolyte, which affects ion diffusion—a known problem for layered membrane devices—and affects both the capacity and rate performance.
A step-by-step vacuum filtration process is used to form the membrane structure, and the amount of graphene oxide used in the filtration solutions can be adjusted to precisely tune t he thickness of each layer. Irradiation of the dried membrane with UV light then reduces the graphene oxide to rGO with assistance from the TiO2.
The full story is available below.
Source: Advanced Science News