I have recently been reading about the amazing discovery of a super-material: Graphene. This one carbon-layer chemical is not only one of the most resistant materials ever known, but also one of the best heat and electric conductors.

At some point, the article mentioned that the implementation of graphene in batteries - such as the lithium ion battery - would revolutionize the industry. I then found in a closet the dusty chemistry book we used in school, and I took a look at the electrochemistry section (I still remember I had enjoyed it back then).

Now that I understand - or rather believe to understand - again how a Lithium-ion battery works, I can't figure out how graphene should contribute to its improvement. Apparently, both electrodes are made of materials that can incorporate lithium ions into their crystal structure and release them easily. One would, therefore, typically employ a lithium metal oxide such as $\text{LiCoO}_2$ as cathode and graphite as anode. (By the way, what could you use as electrolyte?)

Anyhow, as I read in this paper, graphene is usually somehow incorporated to the cathode... Notwithstanding, I don't understand how this should improve the conventional lithum batteries. What are its key properties in this process?

Please consider that I am by no means a professional chemist, but rather chemistry enthusiast who has the knowledge of high-school. Thanks in advance.

  • 2
    $\begingroup$ As electrolyte is usually used Li[PF6] dissolved in mixture of dialkylcarbonates. ( esters of carbonic acid). Using graphene can improve availability of the carbon layers for Li+ ions, compared to graphite. $\endgroup$ – Poutnik Sep 17 at 17:37
  • $\begingroup$ The shape and electronic structure in graphene also contributes to its high conductivity which means that basically electrons can flow through it more easily then other materials $\endgroup$ – dval98 Sep 19 at 18:02

Lithium has a standard redox potential equal to -$3.04$ V. Coupled with any compound at the cathode, it could hardly produce cells yielding more than $4$ Volts, because part of the available energy is needed and lost to extract the external electron of the Lithium atom. The performance of a cell built with a Lithium anode could be more important if the Lithium was already ionized. That's what is done with graphene. When introducing Lithium atom in a graphene structure, its electron is not so strongly attracted by the Lithium nucleus. Lithium inserted between graphene layers behaves as if it was already partly ionized. That is why Lithium in graphene produces an anode which can deliver about $5$ Volts if coupled with a convenient cathode made of Lithium and Cobalt(III) oxides. Graphene plus Lithium may be considered as a mixture of Lithium ions $\ce{Li+}$ and "nearly free" electrons delocalized in the graphene structure.

| improve this answer | |
  • $\begingroup$ Thanks @Maurice for the answer! There is one question I have left: you claim that "When introducing Lithium atom in a graphene structure, its electron is not so strongly attracted by the Lithium nucleus" ... why does this happen? $\endgroup$ – Dr. Mathva Sep 26 at 14:35
  • $\begingroup$ @ Dr. Mathva. Generally speaking, an electron gets more stable if the limits of its domain of existence are increasing. So when the lithium atom touches the huge $\pi$ system made of the infinite number of $sp^2$ Carbon atoms present in the graphene assembly, this lithium atom has tendency to offer its electron to the graphene $\pi$ layer $\endgroup$ – Maurice Sep 26 at 16:26

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.