TY - JOUR
T1 - Nanoscale probing of voltage activated oxygen reduction/evolution reactions in nanopatterned (LaxSr1-x)CoO3-δ cathodes
AU - Leonard, Donovan N.
AU - Kumar, Amit
AU - Jesse, Stephen
AU - Biegalski, Michael D.
AU - Christen, Hans M.
AU - Mutoro, Eva
AU - Crumlin, Ethan J.
AU - Shao-Horn, Yang
AU - Kalinin, Sergei V.
AU - Borisevich, Albina Y.
PY - 2013/6
Y1 - 2013/6
N2 - Bias-dependent mechanisms of reversible and irreversible electrochemical processes on a (La0.5Sr0.5)2CoO 4±δ modified (LaxSr1-x)CoO 3- surface are studied using dynamic electrochemical strain microscopy (D-ESM). The reversible oxygen reduction/evolution process is activated at voltages as low as 3-4 V and the degree of transformation increases linearly with applied bias. The irreversible processes associated with static surface deformation become apparent above 10-12 V. Post-mortem focused-ion milling combined with atomic resolution scanning transmission electron microscopy and electron energy loss spectroscopy is used to establish the mechanisms of irreversible transformations and attribute it to amorphization of the top layer of material. These studies both establish the framework for probing irreversible electrochemical processes in solids and illustrate rich spectrum of electrochemical transformations underpinning electrocatalytic activity in cobaltites.
AB - Bias-dependent mechanisms of reversible and irreversible electrochemical processes on a (La0.5Sr0.5)2CoO 4±δ modified (LaxSr1-x)CoO 3- surface are studied using dynamic electrochemical strain microscopy (D-ESM). The reversible oxygen reduction/evolution process is activated at voltages as low as 3-4 V and the degree of transformation increases linearly with applied bias. The irreversible processes associated with static surface deformation become apparent above 10-12 V. Post-mortem focused-ion milling combined with atomic resolution scanning transmission electron microscopy and electron energy loss spectroscopy is used to establish the mechanisms of irreversible transformations and attribute it to amorphization of the top layer of material. These studies both establish the framework for probing irreversible electrochemical processes in solids and illustrate rich spectrum of electrochemical transformations underpinning electrocatalytic activity in cobaltites.
KW - cobaltites
KW - electrochemical strain microscopy
KW - oxygen vacancy ordering
KW - scanning transmission electron microscopy
KW - solid oxide fuel cells
UR - http://www.scopus.com/inward/record.url?scp=84878651681&partnerID=8YFLogxK
U2 - 10.1002/aenm.201200681
DO - 10.1002/aenm.201200681
M3 - Article
AN - SCOPUS:84878651681
SN - 1614-6832
VL - 3
SP - 788
EP - 797
JO - Advanced Energy Materials
JF - Advanced Energy Materials
IS - 6
ER -