Korean researchers have successfully developed sponge-like graphene aerogel electrode material using graphene and a polymer. This is a graphene battery. The newly-developed battery is ten times as small as existing ones, but can show the same product performance.
A research team headed by Park Ho-seok, professor of the School of Chemical Engineering at Sungkyunkwan University, announced on Feb. 1 that it has succeeded in developing a very porous graphene aerogel electrode material by combining polyvinyl alcohol and graphene.
Studies on developing high-capacity and rapidly-chargeable batteries are underway worldwide. It is necessary to compress devices in order to supply energy in extreme conditions. However, when existing graphene-based batteries are compressed by 30 percent, product performance suffers owing to the destruction of the inside structure.
After inducing a chemical reaction between polyvinyl alcohol and graphene in a state of solution, the research team was able to develop a graphene aerogel electrode material that is easily compressed and highly durable, thanks to a great number of pores inside. Aerogel, which is called the lightest solid, is a porous ultralight material. An estimated 90 to 99.9 percent of the material is composed of air, and pores smaller than 100 nanometers form a 3D web.
Polyvinyl alcohol is combined between graphenes like tangled thread, and thus when it is compressed with outside pressure, pores of graphene aerogel do not stuck together, according to the research team. The structure of graphene does not damage, either.
When the battery became 10 times smaller using graphene aerogel, its performance was similar to that of existing graphene batteries with the same size. Moreover, it was able to maintain the same product performance after it went through the compression and restoration process for more than 10 million times.
The graphene aerogel electrode material is expected to be utilized in the energy storage equipment of electric cars, mobile devices, and space ships, which have been hard to develop using conventional batteries, due to limits in volume and weight.
High porosity combined with mechanical durability in conductive materials is in high demand for special applications in energy storage under limiting conditions, and it is fundamentally important for establishing a relationship between the structure/chemistry of these materials and their properties. Herein, polymer-assisted self-assembly and cross-linking are combined for reduced graphene oxide (rGO)-based aerogels with reversible compressibility, high elasticity, and extreme durability. The strong interplay of cross-linked rGO (x-rGO) aerogels results in high porosity and low density due to the re-stacking inhibition and steric hinderance of the polymer chains, yet it makes mechanical durability and structural bicontinuity possible even under compressive strains because of the coupling of directional x-rGO networks with polymer viscoelasticity. The x-rGO aerogels retain over 140% and over 1400% increases in the gravimetric and volumetric capacitances, respectively, at 90% compressive strain, showing reversible change and stability of the volumetric capacitance under both static and dynamic compressions; this makes them applicable to energy storage devices whose volume and mass must be limited.
SOURCES – Business Korea
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