No abstract

The CeScSZ powders with ceria-doped content were synthesized by the co-precipitation process. The crystal lattice parameter and XRD peak pattern of powders were investigated with the increase of calcination temperature and the change of ceria-doping content at a certain calcination temperature. Moreover, ionic conductivities of the CeScSZ powders were studied in the range of 500 to 900°C. Electrolyte film was fabricated using the synthesized 1Ce10ScSZ powder and single cell of SOFC with anode-supported electrolyte was fabricated by a tape casting and co-sintering process. As a result, the SOFC cell showed power density of 1.2 W/cm 2 at 2 A/cm 2 , 800°C with low ohmic resistance of under 0.1 Ω·cm 2 .

Olivine-structured LiMnPO4 has attracted broad attention as a potential cathode material of Li-ion battery for EV application [1-2], which has some advantage with a higher energy density, higher redox potential and lower cost, etc. However, this material showed a poor electrochemical performance due to the low electronic conductivity [3-4]. Therefore, many researches have been performed to improve the electrochemical properties of LiMnPO4 material by the particle size reduction, cation doping and carbon coating, etc. [5-6]. In here, we studied nano-sized LiMnPO4/C composite materials with a high crystallization prepared using a modified co-precipitation method including a grinding mill and heat treatment process. As a result, the cell showed a good discharge capacity of 145mAh/g and a discharge potential of 3.8V. Furthermore, as the LiMnPO4/C material was combined with Li2MnO3-based material, the LiMnPO4/C composite materials showed a better electrochemical characteristic of above 200mAh/g at 0.05C. In summary, the nano-sized LiMnO4 material with a high crystallization shows good electrochemical properties at room temperature. References [1] J.N. Reimers, J.R. Dahn, J. Electrochem. Soc. 139 (1992) 209. [2] D.K. Kim, P. Muralidharan, H.-W. Lee, R. Ruffo, Y. Yang, C.K. Chan, H. Peng, R.A. Huggins, Y. Cui, Nano Letter 8 (11) (2008) 3948–3952. [3] N.N. Bramnik, H. Ehrenberg, Journal of Alloys and Compounds 464 (2008) 259–264.4) [4] J. Yang, J.J, Journal of The Electrochemical Society 153 (4) (2006) A716–A723 [5] T. Drezen, N.-H. Kwon, P. Bowen, I. Teerlinck, M. Isono, I. Exnar, Journal of Power Sources 174 (2007) 949–953. [6] A.V. Murugan, T. Muraliganth, A. Manthiram, Journal of The Electrochemical Society 156 (2) (2009) A79–A83

Nanocrystalline Yb-doped scandia-stabilized zirconia (6Yb4ScSZ) powders are prepared using co-precipitation process. The effects of calcination treatments on factors such as phase evolution, crystallite size, and specific surface area are investigated. The synthesized electrolyte powders have a high specific area of 25 m 2 g ¹1 , nanocrystalline size of 17 nm and ionic conductivity of 0.7 S cm ¹1 at 800°C with a cubic structure. Solid oxide fuel cell (SOFC) with anode-supported electrolyte, in which the electrolyte layer consists of nanocrystalline 6Yb4ScSZ powders calcined at 850°C, is fabricated by tape casting and co-sintering. The opencircuit voltage of the SOFC single cell is approximately 1.07 V at 800°C, indicating negligible leakage of fuel through the electrolyte layer. As a result, power density of 1.30 W cm ¹2 is obtained at 2.0 A cm ¹2 and 800°C due to the drastic reduction of ohmic resistance in the SOFC cell.

Recently, many sorts of lithium batteries have been studied such as all solid and lithium-air batteries etc., for EV and ESS applications. Especially, all solid battery is one of the candidates for a large-sized battery in regard of the safety problem. Garnet-type LLZO electrolyte has good advantages with a high ionic conductivity and electrochemical potential window. However, it is reported that there are difficulties to prepare LLZO(Li7La3Zr2O12) pellets with high relative density. In this study, LLZO material was doped by the different elements of Al by co-precipitation process. Furthermore, we studied the effects of lithium excess concentration of Al-doped LLZO. We investigated not only the change of cubic and tetragonal structure but also electrochemical properties according to the synthesis conditions. As a result, ionic conductivity of Al-doped LLZO material was about 3.1x10-4 S/cm at room temperature, indicating a wide electrochemical window of 0~5.5V. Furthermore, we will introduce the electrochemical properties of unit cell using LLZO material in more detail.