Preparation of a Reduced Graphene Oxide Wrapped Lithium-Rich Cathode Material by Self-Assembly

• Published in: Chemistry, an Asian journal an Asian journal, 2014-10, Vol.9 (10), p.2946-2952
• Main Authors: Lim, Sung Nam, Ahn, Wook, Yeon, Sun-Hwa, Park, Seung Bin
• Format: Article
• Language: English
• Subjects: cathode materials; Chemistry; graphene; lithium-ion batteries; Plasma; polydiallyldimethylammonium chloride; self-assembly; Spectrum analysis
• ISSN: 1861-4728; 1861-471X
• DOI: 10.1002/asia.201402517

A lithium‐rich cathode material wrapped in sheets of reduced graphene oxide (RGO) and functionalized with polydiallyldimethylammonium chloride (PDDA) was prepared by self‐assembly induced from the electrostatic interaction between PDDA–RGO and the Li‐rich cathode material. At current densities of 1000 and 2000 mA g−1, the PDDA–RGO sheet wrapped samples demonstrated increased discharge capacities, increasing from 125 to 155 mA h g−1 and from 82 to 124 mA h g−1, respectively. The decreased resistance implied by this result was confirmed from electrochemical impedance spectroscopy results, wherein the charge‐transfer resistance of the pristine sample decreased after wrapping with the PDDA–RGO sheets. The PDDA–RGO sheets served as a protective layer sand as a conductive material, which resulted in an improvement in the retention capacity from 56 to 81 % after 90 cycles. Li on the GO: A Li‐rich cathode material wrapped in sheets of reduced graphene oxide (RGO) is prepared by self‐assembly. In the presence of RGO on the cathode material, the Li‐rich cathode shows a capacity of 124 mA h g−1 at 2000 mA g−1 in comparison to 82 mAh g−1 for the bare cathode. The cycle performance is also enhanced from 56 to 81 % after 90 cycles. PDDA=polydiallyldimethylammonium chloride.