Lithium Powder Electrode As Anode in Lithium-Oxygen Batteries

Wednesday, 8 October 2014
Expo Center, 1st Floor, Center and Right Foyers (Moon Palace Resort)
S. Hwang, S. M. Cho, B. S. Koo, and W. Y. Yoon (Department of Materials Science and Engineering, Korea University)
The rechargeable non-aqueous lithium-air (O2) battery system is a promising to apply the large scale storage system such as electric vehicle. It can store much higher theoretical energy density than regular Li-ion batteries. Nevertheless this advantage, Li-O2 cell has the problems such as polarization of the oxygen reduction reaction (ORR), decomposition of the organic electrolyte and dendrite growth on the Li metal anode. Li dendrite can make dead Li which significantly drop the cycle retention. Also Li dendrite growth can occurs the unstable solid electrolyte interface (SEI) layer, it is promote the electrolyte decompose. In this study we use Li powder electrode (LPE) instead of the Li metal anode.

 The Li powder was made by droplet emulsion technique (D.E.T) (the diameter of lithium powder is 10μm). A Li powder was revealed effective to reduce dendrite growing by the previous study of our group. To make the LPE, we loaded 20mg Li powder on the 15 Φ Sus-mesh and pressed 20kgcm-2. To compose the O2 cathode, Poly (vinylidene fluoride) (PVdF), Ketjen black (KB) carbon and MnO2 catalysts were mixed by 2: 4: 4 wt. %. The current collector of O2cathode was Ni foam and punched 14 Φ. The electrolyte was used by a 1M LiTFSI in TEGDME. The morphology of electrode was pictured by field emission scanning electron microscope (FE-SEM).

 To estimate the galvanostatically electrochemical properties we analyze the impedance data, voltage profile and cycle data. The rate of current is 100mAg-1 and limited the time at 10 hours in charge and discharge respectively. In voltage profile we check there a stable cycle process until 40cycles. Li powder has much stable interface reaction than Li metal, it can possible to reduce the over potential at the charge/discharge and make good cycle ability. To analyze the morphology and chemical reaction after cycle was estimated by the FE-SEM, TEM, XPS and FT-IR.

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