CONICET | Buscador de Institutos y Recursos Humanos

Rechargeable lithium ionbatteries (LIB) are energy storage devices with multiple technologicalapplications: from its use in portable electronic devices up to electric cars.Currently, lithium ion batteries are marketed based on graphite anodes becauseit is an inexpensive material with relatively high storage lithium ions. Thismaterial has a theoretical storage capacity of 372 mAh/g, which corresponds tothe intercalation of lithium ions into graphite to form LiC6.The challenge in this technology is to increase the density of stored energywithout increasing its weight or volume, at the same time maintaining its durabilityand safety. That is why there are numerous attempts of scientists andtechnologists to develop new and better materials for anodes and cathodes ofLIB. Recently, synthesized nano-wires of graphite oxide nanotubes frommulti-walled carbon have exceeded the storage capacity of lithium compared toother carbonaceous materials [1-2]. A capacityof 460 mAh/g after 10 cycles of charge/discharge has been reported for graphenenanowires. Something similar happens with graphite oxide. Understanding these structuresat the theoretical level is fundamental to achieve understandings of thepossibilities and limitations of these materials with respect to their abilityof storing lithium ions. In this work the lithiation of reduced graphite oxide (RGO) based on firstprinciples calculations was analyzed. The Quantum-Espresso code was employed inorder to perform density functional theory calculations. The structure andstability of different lithium charge states was studied, with the finding thatthe lithiation potentials predicted are within the range of thoseexperimentally observed for these materials. Finally, the chemical nature ofthe bond formed between lithium atoms and the structures proposed is presented,concluding that the interaction of the Li atom with RGO is totally differentfrom that between Li and pure graphite [3].