Redox-Active Alkali Insertion Materials as Inner Contact Layer in All-Solid-State Ion-Selective Electrodes

Abstract

Lithium insertion materials, such as LiFePO4, have been widely studied as the electrode materials for rechargeable batteries. Alkali ions can be reversibly inserted/extracted into/from their crystal lattices associated with electrochemical redox. In this study, we apply lithium, sodium, and potassium insertion materials as inner contacting layers for the all-solid-state ion-selective electrodes which are covered with the outer ion-selective poly(vinyl chloride) membrane containing ionophore and plasticizer. The introduction of alkali insertion materials layer between Pt substrate and ion selective membrane is highly efficient for the stabilization of membrane potential and its prompt response when alkaline ion activity in analyte changes compared to those of the electrode without alkali insertion materials. Electrochemical measurements reveal that alkali insertion materials as the inner contact layers stabilize the membrane potential because of drastic reduction of interface resistance at the electrode, and thus improves ion-sensing performance.

An Integrated Glucose Sensor with an All-Solid-State Sodium Ion-Selective Electrode for a Minimally Invasive Glucose Monitoring System

“…Compared with the potential drift of Pt/PVC (coat wired electrode, CWE), the developed sodium ISE exhibited almost the same stability as that obtained using a Pt/LixFePO4(insertion)/PVC (Li ionophore) [13] (Figure 7). The good stability performance of carbon/Na0.33MnO2/PVC (DD16C5) was revealed in this study for the first time.…”

“…The insertion materials layers are ion/electron mixed conductor, it makes ionic and electronic communication possible at the interface between the ion-selective membrane and Pt or carbon electrode. As a result, the electrode impedance is significantly reduced and electrode potential is effectively stabilized [13].…”

“…Although coated-wire electrodes, metallic wire electrodes directly covered with an ion-selective membrane has been studied as all-solid-state ISEs since 1971, they generally show insufficient potential stability. To achieve the potential stability and miniaturization of sodium ISEs, an insertion material Na0.33MnO2 has been studied for all-solid-state ISEs [12,13]. Komaba et al reported that the ISE using Na0.33MnO2 as an inner contact layer is highly efficient for stabilization [13].…”

“…To achieve the potential stability and miniaturization of sodium ISEs, an insertion material Na0.33MnO2 has been studied for all-solid-state ISEs [12,13]. Komaba et al reported that the ISE using Na0.33MnO2 as an inner contact layer is highly efficient for stabilization [13]. This stabilization of the membrane potential was because the interface resistance at the electrode reduced drastically.…”

Interkalationsverbindungen als Referenzelektroden für reproduzierbare und robuste ionenselektive Festkontaktelektroden

“…IC‐basierte ISE wurden erstmals von Komaba et al. vorgestellt und wiesen dabei eine Potentialstabilität von ±5 mV über einen Zeitraum von 15 Tagen auf . Das Problem lag allerdings darin, dass diese Elektroden eine individuelle elektrochemische Konditionierung benötigten; ebenso wurden weder der Absolutwert noch die Reproduzierbarkeit des Standardpotentials beschrieben.…”