Graphite intercalation compounds may offer keys to prolonging battery life
In 2012-2013, an international research collaborative discovered a phenomenon that could be observed via optical microscope during the stage transitions in graphite intercalation compounds. It took team leader Dr. Ayrat M. Dimiev six years of further research, including additional experiments at Kazan Federal University, to fully comprehend the driving forces behind the observed phenomena.
The experiments were conducted with participation from Ph.D. graduate Ksenia Shukhina. An important breakthrough came from the use of ultrafast Raman mapping of the graphite surface during stage transitions. The joint Russian-American paper appeared in The Journal of Physical Chemistry C.
Graphite intercalation compounds (GICs) are formed by insertion of certain atomic and molecular species between the graphenelayers of graphite. The resulting compounds possess a range of unique properties, which are not specific for the parent materials. Among the most intriguing properties of GIC is its superconductivity, a discovery that triggered much interest. Depending on the electrochemical potential of the intercalant and the respective charge on the graphene layers, graphite forms structures where one, two or more graphene layers are sandwiched between the two layers of intercalant. The resulting compounds are referred to as stage-1, stage-2, and stage-3 GICs, respectively. Despite intensive and long-lasting research on GICs, the mechanism of the stage transitions remains obscure.
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