Graphene to prepare higher capacity lithium battery

Graphene to prepare higher capacity lithium battery

Researchers at the US Department of Energy's Lawrence Berkeley National Laboratory have created a nanocomposite of graphene and tin that enables high-capacity energy storage in renewable lithium-ion batteries. By sandwiching the tin between the graphene sheets, the researchers created a new lightweight "sandwich" structure that improved battery performance.

“For electric cars, you need a lightweight battery that can be charged quickly, and you can still maintain the charging capacity after repeated use,” said Yuegang Zhang, who is the molecular casting department of Berkeley Labs. Molecular Foundry, a researcher, led the research at the Inorganic Nanostructures Facility. “Here, what we have shown is a reasonably designed nanoscale structure that can be run without additives or binders to improve battery performance.”

Graphene is a monoatomic thick "chicken line" lattice carbon atom with extraordinary electrical and mechanical properties that far exceeds silicon and other traditional semiconductor materials. In the previous graphene study, Zhang Yuegang and his colleagues emphasized the application of electronic devices.

In this study, the team assembled layered alternating graphene and tin to create a nanocomposite. To create this composite, a layer of tin film is deposited onto the graphene. Next, another layer of graphene sheets was transferred onto the tin film. By repeating this process, a composite material can be made and then heated to 300 degrees Celsius (572 degrees Fahrenheit) in a hydrogen and argon atmosphere. During this heat treatment, the tin film is converted into a series of columns, increasing the height of the tin layer.

“The formation of these nanocolumns from tin films is very special for this system. We have found that the distance between the upper and lower graphenes also changes to accommodate the height variation of the tin layer,” Li Wen Ji) said that he is a postdoctoral researcher in the foundry department. Ji Liwen is the lead author and Zhang Yuegang, a paper by the author of the communication, reported the study and published it in the journal Energy and Environmental Science.

In these new nanocomposites, the change in the height of the graphene layer contributes to the electrochemical cycling process of the battery, since the volume change of tin improves the performance of the electrode. In addition, this adjustable behavior means that the battery can be quickly and repeatedly charged without degradation, which is critical for electric vehicle rechargeable batteries.

“We have a large battery program at Berkeley Labs, and we are able to manufacture highly recyclable battery cells. Through our interaction with the Carbon Cycle 2.0 program, researchers in the Materials Science Department benefit from quality Battery facilities and personnel, in addition, we learned what to use to make better electrodes," said joint author Battaglia, who is the project manager for the Advanced Energy Technology Division of the Environment and Energy Technology Division at Berkeley Labs. “In return, we have a window that allows scientists who develop next-generation materials to talk about these requirements.”

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