Graphene battery has (HPG) tech to get high-power
We use batteries in many gadgets but a lot of people complain from short life of batteries, Due to the urgent demand for sustainable energy systems and portable energy storage devices, the Li-S battery has been cited as the most promising alternative for next-generation energy storage devices, due to its high theoretical energy density of 2600 Wh kg-1, low cost, and eco-friendliness. Despite these advantages, the practical application still suffers from a formidable challenge due to the intrinsic insulation of sulfur and lithium sulfides, the dissolution of polysulfides with a shuttle effect, and the huge volume change of cathode materials during operation.
So scientists all over the world work hard to cross this disadvantages and seeking to develop hierarchical nanocarbon materials like Hierarchical Porous Graphene (HPG) because Graphene battery with tunable structural hierarchies and surface features for use as Li-S cathode scaffolds to address these issues effectively.
Researchers from China, led by Prof. Qiang Zhang in Tsinghua University, has developed a novel kind of Hierarchical Porous Graphene (HPG) via a versatile Chemical Vapor Deposition (CVD) on CaO templates for high-power lithium-sulfur (Li-S) batteries. This work is published in the journal Advanced Functional Materials. They try Structural hierarchy is the cornerstone of the biological world because it’s as well as the most important lesson that we have learned from nature to develop ingenious hierarchical porous materials for various applications in energy conversion and storage.
Hierarchical porous materials exhibit porosities on more than one length scale with different properties and roles, respectively. It is important for the improvement in Li-S battery performances. “However, strategies with a multistep process or/and multiscale templates are dominantly employed to obtain hierarchical porosities. It is always complicated and unfavorable to the structure regulations,” says Cheng Tang, a graduate student, and the first author. For the first time, Cheng proposed the hierarchical porous CaO particles as effective catalytic templates for the facile CVD growth of graphene. CaO is a very common and promising material with a low cost, easy purification, and promising cyclic utilization.
Additionally, various hierarchical structures can be readily obtained for CaO, making it a versatile strategy to fabricate HPG materials with tunable structural hierarchy. Based on this concept, they obtained a hierarchical porous structure of graphene with abundant microsized inplane vacancies, messed wrinkled pores, and macro sized strutted cavities. It can serve as a favorable scaffold for cathodes of Li-S batteries with enhanced utilization of sulfur, high discharge capacity and efficiency, superior stability, and excellent rate capability.
The small mesopores facilitate the entrapment of sulfur and polysulfides; the micropores and defective graphene layers with a high SSA accommodate a high sulfur loading with intimate affinity the interconnected large mesopores and macropores shorten the transport distance of ion and electrolyte.