%0 Conference Paper
%A Tsai, Chih-Long
%A Vinod Chandran, C.
%A Besmehn, Astrid
%A Uhlenbruck, Sven
%A Gehrke, Hans-Gregor
%A Reppert, Thorsten
%A Heitjans, P.
%A Guillon, Olivier
%T Lithium Dendrite Growth in Hot Pressed Ta-Substituted Li7La3Zr2O12
%M FZJ-2015-04606
%D 2015
%X Lithium metal has the lowest native electrochemical potential, -3.4 V vs. H2, and extremely high specific capacity, 3860 mA h/g, and low density, 0.59 g/cm3. These properties make it an ideal anode for rechargeable batteries as well as for next generation Li-S and Li-air batteries. However, the use of metallic Li in a rechargeable battery is not succesful until now due to the difficulty of suppressing the growth of Li dendrite. Theoretical calculations suggest the dendrite can be suppressed if the used electrolyte has a shear modulus of more than twice that of the metallic Li, ~109 Pa, or a Li-ion transfer number tLi+ approaching1. Therefore, the garnet structured Li7La3Zr2O12 (LLZ) solid state Li-ion conductor is an ideal material for preventing dendrite growth because of its unity ionic transfer number, high mechanical strength and chemically stability in contact with metallic Li.However, Li dendrite formation was reported by Yamamoto et al.  from their Al-substituted LLZ and Ta-substituted LLZ with unclear reason. In this research, two samples which are Al contaminated and Al free Ta-substituted LLZ were fabricated by hot pressing. Both samples have relative densities >99% and total conductivities ~1 mS/cm at room temperature. During the dendrite studies, impedance measurements show rapid decrease in total resistances within a couple of hundred seconds which indicates the dendrite can be formed in such a high dense ceramic in a short time. Solid-State NMR shows metallic Li was found inside the dense pellet which was also supported by XPS. The dendrite test results and the possible reasons for the formation of the Li dendrite will be discussed in this presentation.
%B 20th International Conference on Solid State Ionics
%C 15 Jun 2015 - 19 Jun 2015, Keystone, Colorado (USA)
Y2 15 Jun 2015 - 19 Jun 2015
M2 Keystone, Colorado, USA
%F PUB:(DE-HGF)6
%9 Conference Presentation
%U https://juser.fz-juelich.de/record/202342