| 학회 | 한국재료학회 |
| 학술대회 | 2018년 봄 (05/16 ~ 05/18, 삼척 쏠비치 호텔&리조트) |
| 권호 | 24권 1호 |
| 발표분야 | C. 에너지 재료 분과 |
| 제목 | Free-Standing Iridium-Coated Polyimide Nanofiber Membrane as Carbon-Free Air Cathode for Flexible Lithium-Oxygen Batteries |
| 초록 | One of key issues limiting practical implementation of lithium-oxygen (Li-O2) batteries is short-cycle life with low round-trip efficiency; this is mainly attributed to carbon-based cathode part in the battery cell (e.g. formation of Li2CO3 stemming from interface between discharge product (Li2O2) and carbon). Herein, we fabricated free-standing Iridium (Ir)-coated polyimide nanofiber membrane (PI@Ir NF) as carbon-free air cathode for flexible Li-O2 batteries. Firstly, free-standing PI NF was synthesized via electrospinning of polyimide solution (commercially available polyimide resin dissolved in N,N-dimethylformaide (DMF)) followed by heat treatment for subsequent curing.[1] Then, through sputtering with metallic Ir target (RF-sputtering(HVS-210) with a power of 80 W and a base pressure of 1.5 x10-2 torr.), Ir overlayer were coated on entire surfaces of the PI NFs. The designed PI@Ir NFs showed greatly important features as porous cathode: (1) Mechanically durable PI NFs without reactive carbon in electrolyte provide flexible, porous and light-weight matrix for diffusing O2 and accommodating Li2O2 in large void reservoirs. (2) Conductive and catalytic Ir overlayers serve as not only catalyst for discharge (2Li+ + 2e- =＞ Li2O2) and charge (Li2O2 =＞ 2Li+ + 2e-) reactions, but also current-collecting region and facile pathway for electron transport. The PI@Ir NFs exhibit a highly stable capacity at a fixed capacity of 1000 mAh g-1 for over 100 cycles. Based on ex-situ SEM, XRD, TEM and XPS analyses, we conducted close-investigation of reaction products in light of morphology, parasitic side reactions. Flexible pouch Li-O2 cell was successfully fabricated and applied as power source for electronic device (LED with operating voltage of 5.0 V). It is demonstrated that this strategy of cathode architecture for creating flexible and conducting nanopaper will give an applicable solution for advanced Li-O2 batteries. [1] Lee, J.; Lee, C.-L.; Park, K.; Kim, I.-D. Synthesis of an Al2O3-coated polyimide nanofiber mat and its electrochemical characteristics as a separator for lithium ion batteries. J. Power Sources 2014, 248, 1211−1217. |
| 저자 | Ji-Won Jung, Il-Doo Kim, Sang-Joon Kim, Jong-Seok Nam |
| 소속 | Korea Advanced Institute of Science and Technology |
| 키워드 | <P>Iridium; lithium-oxygen battery; cathode; carbon-free electrode; sputter</P> |
