TY - JOUR
T1 - Detecting Potassium Ion Gradients at a Model Graphitic Interface
AU - Barton, Zachary J.
AU - Hui, Jingshu
AU - Schorr, Noah B.
AU - Rodríguez-López, Joaquín
N1 - Publisher Copyright:
© 2017 Elsevier Ltd
PY - 2017/7/1
Y1 - 2017/7/1
N2 - Potassium ion batteries (KIBs) are gaining attention as attractive, low-cost alternatives to lithium ion batteries (LIBs). Emerging KIB materials are not yet fully understood, so in situ characterization techniques are being developed to address the similarities and differences to the operation of LIB materials, including aspects of interfacial ion transfer and solid electrolyte interphase (SEI) formation. Here, we introduce the use of Hg disc-well microelectrodes as probes in scanning electrochemical microscopy (SECM) for the detection of K+ gradients on an operating graphitic material. Electrochemically controlled amalgamation and stripping reactions on these probes permit their accurate positioning near a conductive surface, and the detection of local concentration changes once the substrate is biased to intercalate K+. K+ reduction into the Hg phase follows a behavior similar to that of Li+ and Na+ and yields an electrochemical response that is used to evaluate local substrate reactivity. Using these probes in situ, we demonstrate the reversible intercalation of K+ on a surface site of patterned highly oriented pyrolytic graphite (HOPG), a model interface for carbonaceous KIB materials. Our method affords a direct measurement of localized K+ fluxes, which are not resolvable through bulk electroanalytical techniques, thus making our approach potentially informative about reaction mechanisms for nascent KIB-based energy storage technologies.
AB - Potassium ion batteries (KIBs) are gaining attention as attractive, low-cost alternatives to lithium ion batteries (LIBs). Emerging KIB materials are not yet fully understood, so in situ characterization techniques are being developed to address the similarities and differences to the operation of LIB materials, including aspects of interfacial ion transfer and solid electrolyte interphase (SEI) formation. Here, we introduce the use of Hg disc-well microelectrodes as probes in scanning electrochemical microscopy (SECM) for the detection of K+ gradients on an operating graphitic material. Electrochemically controlled amalgamation and stripping reactions on these probes permit their accurate positioning near a conductive surface, and the detection of local concentration changes once the substrate is biased to intercalate K+. K+ reduction into the Hg phase follows a behavior similar to that of Li+ and Na+ and yields an electrochemical response that is used to evaluate local substrate reactivity. Using these probes in situ, we demonstrate the reversible intercalation of K+ on a surface site of patterned highly oriented pyrolytic graphite (HOPG), a model interface for carbonaceous KIB materials. Our method affords a direct measurement of localized K+ fluxes, which are not resolvable through bulk electroanalytical techniques, thus making our approach potentially informative about reaction mechanisms for nascent KIB-based energy storage technologies.
KW - Alkali Ion Intercalation
KW - Mercury Electrode
KW - Potassium Ion Battery
KW - Scanning Electrochemical Microscopy (SECM)
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U2 - 10.1016/j.electacta.2017.04.105
DO - 10.1016/j.electacta.2017.04.105
M3 - Article
AN - SCOPUS:85018348517
SN - 0013-4686
VL - 241
SP - 98
EP - 105
JO - Electrochimica Acta
JF - Electrochimica Acta
ER -