Anais da 43ª Reunião Anual Virtual da SBQ

Here, we report the synthesis and application of a hybrid material composed of Fe3O4 nanoparticles embedded in nitrogen-doped graphene sheets (Fe3O4@N-doped graphene) as a negative electrode for lithium-ion batteries. We studied the influence of N-doped graphene on the storage capacity of Fe3O4 using different electrochemical techniques. We determined that the as-prepared Fe3O4 materials presented high-quality crystalline nanostructures. Using cyclic voltammetry and electrochemical impedance spectroscopy techniques, we demonstrated that the N-doped graphene sheets improved the conductivity between the Fe3O4 nanoparticles, allowing a faster charge transfer process than that for pure magnetite nanoparticles, as well as the presence of porous particles in the hybrid composite. The Fe3O4@N-doped graphene hybrid material showed the best Li storage capacity and maintained specific capacity values of 910 mA h g–1 during the first 150 cycles performed at 0.05 A g–1 and 850 mA h g–1 at 0.1 A g–1 during the following 50 cycles, which were near their corresponding theoretical values. Moreover, the N-doped graphene sheets resisted the volume changes that occur during discharge/charge processes, which helped avoid the consequent pulverization that this kind of material suffers in rate capability experiments. We provided a simple and novel method to obtain a material with a higher superficial area and conductivity between particles, allowing great performance as a negative electrode for lithium-ion batteries application.