| 학회 | 한국재료학회 |
| 학술대회 | 2016년 봄 (05/18 ~ 05/20, 여수 디오션리조트 ) |
| 권호 | 22권 1호 |
| 발표분야 | C. 에너지 재료 분과 |
| 제목 | Catecholamine Functionalized Reduced Graphene Oxide - Sulfur Composite as Cathode Material for Lithium Sulfur Batteries |
| 초록 | The quest to drop the non-renewable fuels for electric vehicles started the era of hybrid electric vehicles (HEVS). With this, the demand in the rechargeable batteries has ever since been growing. Li-ion batteries had temporarily solved the problem but their low energy density ~150 Wh / Kg limits its use in HEVs. Among various next generation rechargeable batteries, Lithium-Sulfur (Li-S) batteries has emerged as a potential candidate to replace Li-ion batteries because the former has high theoretical energy density of 2500 Wh/Kg which is almost 7 times higher than the currently used Li-ion batteries. Moreover sulfur has advantages of low price, non-toxicity and abundance as a raw material. However Li-S battery meets few challenges of low S conductivity (10-30), volume expansion upon lithiation (80%), polysulfide dissolution (Li2Sn , 2＜n≤8) in the electrolyte and subsequent shuttle effect. All the reported factors contribute in severe capacity fading in Li-S battery which if overcomed can solve the current problem of shorter mileage in HEVs. To address the major problem of polysulfide dissolution and also to provide electrical conductivity, we propose chemical interaction of 2D functionalized graphene with sulfur as a cathode composite for high stable and high capacity Li-S battery. The use of catecholamine functional groups on graphene oxide (GO) to simultaneously reduce and functionalize reduced graphene oxide (c-rGO) with subsequent sulfur infusion by melt diffusion method has greatly solved the capacity fading problem. To emphasize the importance of introducing catecholamine functional groups, thermally reduced t-rGO/S composite was also tested in which the reduced rGO contains no functional groups. The use of c-rGO/S composite stabilizes the capacity to as high as 700 mAh/g at 0.5C after 100cycles whereas the high electrical resistivity of oxidized graphene-sulfur cathode composite lower the capacity to as low as 300mAh/g at 0.5C after 100 cycles. The thermally reduced rGO/S composite improved the discharge capacity to only 400mAh/g at 0.5C after 100 cycles amid the absence of any polysulfide adsorbing functional groups like the one present in catecholamine functional group. Moreover the effective polysulfide adsorption by c-rGO/S in comparison to GO/S will be shown by in-situ UV-Vis spectroscopy studies. |
| 저자 | Syed Abdul Ahad1, Joo-Hyung Kim2, Do Kyung Kim3 |
| 소속 | 1Department of Materials Science and Engineering, 2Korea Advanced Institute of Science and Technology (KAIST), 3291 Daehak-ro |
| 키워드 | catecholamine; Li-S battery; In-Situ UV-Vis spectroscopy; rGO; chemical interaction; polysulfide dissolution |
