Two-dimensional carbon networks

June 18, 2020

Lithium-ion batteries usually contain graphitic carbons as anode materials. Scientists have investigated the carbonic nanoweb graphdiyne as a novel two-dimensional carbon network for its suitability in battery applications. Graphdiyne is as flat and thin as graphene, which is the one-atomic-layer-thin version of graphite, but it has a higher porosity and adjustable electronic properties. In the journal Angewandte Chemie, researchers describe its simple bottom-up synthesis from tailor-made precursor molecules.

Carbon materials are the most common anode materials in lithium-ion batteries. Their layered structure allows lithium ions to travel in and out of the spaces between layers during battery cycling, they have a highly conductive two-dimensional hexagonal crystal lattice, and they form a stable, porous network for efficient electrolyte penetration. However, the fine-tuning of the structural and electrochemical properties is difficult as these carbon materials are mostly prepared from polymeric carbon matter in a top-down synthesis.

Graphdiyne is a hybrid two-dimensional network made of hexagonal carbon rings bridged by two acetylene units (the "diyne" in the name). Graphdiyne has been suggested as a nanoweb membrane for the separation of isotopes or helium. However, its distinct electronic properties and web-like structure also make graphdiyne suitable for electrochemical applications. Changshui Huang from the Chinese Academy of Sciences, Beijing, and colleagues have investigated the lithium-storage capabilities and electrochemical properties of tailor-made, electronically adjusted graphdiyne derivatives.

The scientists synthesized the graphdiyne derivatives in a bottom-up strategy by adding precursor molecules on a copper foil, which self-organized to form ordered layered nanostructures. Using monomers containing functional groups with interesting electronic properties, the authors prepared functional graphdiynes with distinct electrochemical and morphological properties.

Among these functional groups, those exerting electron-withdrawing effects reduced the band gap of graphdiyne and increased its conductivity, the authors reported. The cyano group was especially effective and, when used as an anodic material, the cyano-modified graphdiyne demonstrated excellent lithium-storage capacity and was stable for thousands of cycles, as the authors reported.

In contrast, when graphdiyne was modified with bulky functional groups (methyl groups) that donate electrons to the graphdiyne network, the authors observed a larger layer spacing, which made the material structure unstable so that the anode only survived a few charge and discharge cycles. The authors also compared both modified graphdiyne materials to an "empty" version where only hydrogen occupied the position of the functional groups in the network.

The authors conclude that modified graphdiyne can be prepared by a bottom-up strategy, which is also best suited to build functional two-dimensional carbon material architectures for batteries, capacitors, and other electrocatalytic devices.
About the Author

Professor Changshui Huang leads the Advanced Carbon for Renewable Energy Group at Qingdao Institute of Bioenergy and Bioprocess Technology, the Chinese Academy of Sciences (CAS), Beijing. The group investigates two-dimensional carbon materials for applications as energy-storage and conversion materials.


Related Batteries Articles from Brightsurf:

New research says Sodium-ion batteries are a valid alternative to Lithium-ion batteries
A team of scientists including WMG at the University of Warwick combined their knowledge and expertise to assess the current status of the Na-ion technology from materials to cell development, offering a realistic comparison of the key performance indicators for NBs and LIBs.

Fast calculation dials in better batteries
A simpler and more efficient way to predict the performance of batteries will lead to better batteries, according to Rice University engineers.

Building the batteries of cells
A new study, led by Dr. Ruchika Anand and Prof.

Researchers create a roadmap to better multivalent batteries
Lithium-ion batteries power everything from mobile phones to laptop computers and electric vehicles, but demand is growing for less expensive and more readily available alternatives.

New NiMH batteries perform better when made from recycled old NiMH batteries
A new method for recycling old batteries can provide better performing and cheaper rechargeable hydride batteries (NiMH) as shown in a new study by researchers at Stockholm University.

Seeing 'under the hood' in batteries
A high-sensitivity X-ray technique at Berkeley Lab is attracting a growing group of scientists because it provides a deep, precise dive into battery chemistry.

Better, safer batteries
For the first time, researchers who explore the physical and chemical properties of electrical energy storage have found a new way to improve lithium-ion batteries.

New catalyst provides boost to next-generation EV batteries
A recent study, affiliated with South Korea's Ulsan National Institute of Science and Technology (UNIST) has introduced a new composite catalyst that could efficiently enhance the charg-discharge performances when applied to metal-air batteries (MABs).

New lithium batteries from used cell phones
Research from the University of Cordoba (Spain) and San Luis University (Argentina) was able to reuse graphite from cell phones to manufacture environmentally friendly batteries.

Safe potassium-ion batteries
Australian scientists have developed a nonflammable electrolyte for potassium and potassium-ion batteries, for applications in next-generation energy-storage systems beyond lithium technology.

Read More: Batteries News and Batteries Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to