TY  - JOUR
AU  - Schleutker, Marco
AU  - Bahner, Jochen
AU  - Tsai, Chih-Long
AU  - Stolten, Detlef
AU  - Korte, Carsten
TI  - On the interfacial charge transfer between solid and liquid Li + electrolytes
JO  - Physical chemistry, chemical physics
VL  - 19
IS  - 39
SN  - 1463-9084
CY  - Cambridge
PB  - RSC Publ.
M1  - FZJ-2017-06938
SP  - 26596--26605
PY  - 2017
AB  - The Li+ ion transfer between a solid and a liquid Li+ electrolyte has been investigated by DC polarisation techniques. The current density i is measured as a function of the electrochemical potential drop Δ[small mu, Greek, tilde]Li+ at the interface, using a liquid electrolyte with different Li+ concentrations. The subject of this experimental study is the interface between the solid electrolyte Ta-substituted lithium lanthanum zirconate (Li6.6La3Zr1.6Ta0.4O12) and a liquid electrolyte consisting of LiPF6 dissolved in ethylene carbonate/dimethyl carbonate (1 : 1). The functional course of i vs. Δ[small mu, Greek, tilde]Li+ can be described by a serial connection between a constant ohmic resistance Rslei and a current dependent thermally activated ion transfer process. For the present solid–liquid electrolyte interface the areal resistance Rslei of the surface layer is independent of the Li+ concentration in the liquid electrolyte. At room temperature a value of about 300 Ω cm2 is found. The constant ohmic resistance Rslei can be attributed to a surface layer on the solid electrolyte with a (relatively) low conductivity (solid–liquid electrolyte interphase). The low conducting surface layer is formed by degradation reactions with the liquid electrolyte. Rslei is considerably increased if a small amount (ppm) of water is added to the liquid electrolyte. The thermally activated ionic transfer process obeys a Butler–Volmer like behaviour, resulting in an exchange current density i0 depending on the Li+ concentration in the liquid electrolyte by a power-law. At a Li+ concentration of 1 mol l−1 a value of 53.1 μA cm−2 is found. A charge transfer coefficient α of ∼0.44 is measured. The finding of a superposed constant ohmic resistance due to a solid–liquid electrolyte interphase and a current dependent thermally activated ion transfer process is confirmed by the results of two former experimental studies from the literature, performing AC measurements/EIS.
LB  - PUB:(DE-HGF)16
C6  - pmid:28948987
UR  - <Go to ISI:>//WOS:000412763700013
DO  - DOI:10.1039/C7CP05213H
UR  - https://juser.fz-juelich.de/record/838295
ER  -