Cobaltite oxide nanosheets anchored graphene nanocomposite as an efficient oxygen reduction reaction (ORR) catalyst for the application of lithium-air batteries

• Published in: Journal of power sources Vol. 288; pp. 451 - 460
• Main Authors: Gnana kumar, G., Christy, Maria, Jang, Hosaeng, Nahm, Kee Suk
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.08.2015
• Subjects: Cubic nanosheets; Disproportionation; Electrokinetics; Interfacial contact; Self assembly; Solid electrolyte interphase; Self assembly; Solid electrolyte interphase; Interfacial contact; Disproportionation; Cubic nanosheets; Electrokinetics
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2015.04.029

The graphene/cubic cobaltite oxide nanosheets (rGO/Co3O4) with a face centered cubic crystalline structure are synthesized and are exploited as effective cathode catalysts in high performance Lithium-air batteries. The morphological images enunciate that 220 nm average diameter of Co3O4 nanosheets are effectively anchored over the graphene sheets and the diameter of individual nanoparticles that construct the cubic nanosheets is 5 nm. The growth and composite formation mechanisms of prepared nanostructures are identified from Raman and FT-IR spectroscopic techniques. rGO/Co3O4 composite exhibits a lower voltage, high discharge capacity of 4150 mAh g−1 and displays superior cyclability without any capacity losses, signifying the excellent rechargeability of the fabricated electrodes. The post mortem analysis of electrodes specify the existence of lithium peroxide (Li2O2), lithium oxide (Li2O) and lithium carbonate (Li2CO3) discharge products, revealing the involved electrochemical reaction of Lithium-air batteries. The excellent electrochemical properties of rGO/Co3O4 composite is due to the combination of rapid electrokinetics of electron transport and high electrocatalytic activity toward oxygen reduction reaction given via the synergetic effects of rGO and cubic Co3O4 nanosheets. These findings provide fundamental knowledge on understanding the influence of morphological and structural properties of graphene based nanostructures toward Lithium-air battery performances. [Display omitted] •Reduction of GO and insitu generation of Co3O4 nanosheets occurred concurrently.•Synergetic interaction between Co3O4 and rGO improved oxygen reduction rate.•Co3O4 centres involved reaction mechanism in Li-air battery is detailed.•rGO/Co3O4 exhibited a higher discharge capacity with an excellent cyclability.•The lithium based discharge products in electrodes are systematically analyzed.