Improving sodium-ion batteries with mechanically robust nanocellular graphene
10 April 2024
Nanocellular graphene, a specialized form of the revolutionary material graphene, is coveted for its ability to improve the performance of electronic devices, energy devices and sensors. But its development has been stymied by cracks that appear during the manufacturing process. Now, researchers have discovered a means to achieve crack-free, robust NCG—something they successfully put to use in a sodium battery.
Schematic illustration for the formation NCG during liquid metal dealloying of amorphous manganese-carbon (Mn-C) alloy in a molten bismuth (Bi) to induce selective dissolution of manganese (Mn) atoms and self-organization of carbon (C) atoms into graphene layers. S.H. Joo & H. Kato.
Graphene comprises two-dimensional sheets of carbon atoms, bonded into a thin hexagonal shape with a thickness of one atom layer. This gives it remarkable physical and chemical properties. Despite its thinness, graphene is incredibly strong, lightweight, flexible, and transparent. It also exhibits extraordinary electrical and thermal conductivity, high surface area, and impermeability to gasses. From high-speed transistors to biosensors, it boasts an unrivaled versatility in applications.
Nanocellular graphene (NCG) is a specialized form of graphene that achieves a large specific surface area by stacking multiple layers of graphene and controlling its internal structure with a nanoscale cellular morphology.
NCG is coveted for its potential to improve the performance of electronic devices, energy devices and sensors. But its development has been stymied by defects that occur during the manufacturing process. Cracks often appear when forming NCG, and scientists are looking for new processing technologies that can fabricate homogeneous, crack-free and seamless NCGs at appropriate scales.
We discovered that carbon atoms rapidly self-assemble into crack-free NCG during liquid metal dealloying of an amorphous Mn-C precursor in a molten bismuth.
—Won-Young Park, a graduate student at Tohoku University
Dealloying is a processing technique that exploits the varying miscibility of alloy components in a molten metal bath. This process selectively corrodes certain components of the alloy while preserving others.
Park and his colleagues demonstrated that NCGs developed by this method exhibited high tensile strength and high conductivity after graphitization. Moreover, they put the material to the test in a sodium-ion battery (SIB).
We used the developed NCG as an active material and current collector in a SIB, where it demonstrated a high rate, long life and excellent deformation resistance. Ultimately, our method of making crack-free NCG will make it possible to raise the performance and flexibility of SIBs - an alternative technology to lithium-ion batteries for certain applications, particularly in large-scale energy storage and stationary power systems where cost, safety, and sustainability considerations are paramount.
—Won-Young Park
Details of the research were published in the journal Advanced Materials.
Resources
Wong-Young Park, Jiuhui Han, Jongun Moon, Soo-Hyun Joo, Takeshi Wada, Yuji Ichikawa, Kazuhiro Ogawa, Hyoung Seop Kim, Mingwei Chen, Hidemi Kato (2024) “Mchanically Robust Self-Organized Crack-Free Nanocellular Graphene with Outstanding Electrochemical Properties in Sodium Ion Battery” Advanced Materials doi: 10.1002/adma.202311792
A lot of good sounding Rhetoric but specific technical details are completely missing.
Posted by: yoatmon | 10 April 2024 at 06:47 AM
Hi yoatman!
I am not sure what details you are looking for.
What they have provided in the linked paper seems reasonable to me for such early stage stuff.
That is particularly so since they say above:
' an alternative technology to lithium-ion batteries for certain applications, particularly in large-scale energy storage and stationary power systems where cost, safety, and sustainability considerations are paramount.'
ie they are not seeking to claim very high energy density, needed for BEVs and so on, but high cycle life and round trip efficiency.
Would I like to see more details?
You bet!
But early days.......
Posted by: Davemart | 10 April 2024 at 09:05 AM