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The ionic liquid 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide was used in the scanning micropipette contact method to extend the electrochemical window of the electrolyte solution and enable the study of lithium‐ion battery materials with higher oxidation potential. Localized electrochemical measurements were performed on lithium iron phosphate particles that were drop‐cast onto a glassy carbon substrate. Investigation of the active materials occurred on a small scale (ca. 10 μm diameter), defined by the area of meniscus contact between the electrolyte solution in the micropipette and the substrate. Our studies showed that the SMCM probe is stable and can be used to analyze high energy lithium‐ion battery materials in the range of 2.5 to 5.1 V vs. Li/Li+. Extended potential, higher efficiency: Scanning micropipette contact method (SMCM) is extended to ionic liquid studies. The potential window for 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI TFSI) ionic liquid is suitable to examine high‐energy lithium‐ion battery materials. The electrochemical properties of lithium iron phosphate (LFP) particles drop‐cast onto a glassy carbon substrate are probed under inert atmosphere. SMCM‐coulombic efficiency of LFP particles in EMI TFSI is estimated to be higher than 90 %. [ABSTRACT FROM AUTHOR]

A new type of an electrochemical flow cell designed for exchangeable ultramicroelectrodes (UMEs) is presented. The cell could be used with up to 8 different UMEs allowing one to use this cell for UME array measurements. The cell was characterized using both empirical data and finite element modeling. Au and Pt UMEs were used to detect catechol simultaneously, demonstrating the ability of this cell to be used as a sensory platform. The electroanalytical response of flow system was validated by direct measurements of H2O2 concentrations. Finally, stochastic nanoparticle measurements were successfully performed using the flow system, highlighting the future possibilities of this system for environmental monitoring. [ABSTRACT FROM AUTHOR]

Titanium has been added to ferritic stainless steels to combat the detrimental effects of intergranular corrosion. While this has proven to be a successful strategy, we have found that the resulting Ti-rich inclusions present on the surface play a significant role in the initiation of other forms of localized corrosion. Herein, we report the effect of these inclusions on the localized corrosion of a stainless steel using macro and micro electrochemical techniques. Through the use of scanning electrochemical microscopy, we observe the microgalvanic couple formed between the conductive inclusions and passivated metal matrix. The difference in local reactivity across the material's surface was quantified using a 3D finite element model specifically built to respect the geometry of the corrosion-initiating features. Combined with electron microscopy and micro elemental analysis, localization of other alloying elements has been reported to provide new insight on their significance in localized corrosion resistance. Localized corrosion: Understanding stabilised stainless steel Using a suite of techniques, the role of Ti-rich inclusions in the localized corrosion of stainless steel has been better understood. For some applications ferritic stainless steels are a good low-cost option because they contain low levels of relatively expensive nickel, however, they are vulnerable to intergranular corrosion. There are methods by which to minimize such unwanted corrosion chemistry, such as creating alloys with stabilizing agents like Ti and Nb. Now, a team, led by Janine Mauzeroll at McGill University, Montreal, Canada, has used a battery of techniques, such as X-ray energy dispersive spectroscopy and scanning electrochemical- and electron- microscopies, to understand the role of Ti-rich inclusions in the Ti-stabilized stainless steel 'SS 444'. Specifically they found that, while Ti does improve bulk corrosion properties, Ti-rich inclusions act as initiation sites for localized corrosion. [ABSTRACT FROM AUTHOR]

The development of a reproducible procedure for the fabrication of Pt disk-shaped microelectrodes with characteristic dimensions ranging from 50 nm to 1 μm in diameter was carried out using a laser pulling technique. The governing physical phenomena involved in their fabrication are discussed, and the importance of adding a critical quartz thinning step in the general procedure is demonstrated. The preparation of the microelectrodes involves sealing a platinum wire inside a quartz tubing using a pipet puller, thinning the composite material (platinum/quartz assembly), and laser pulling it to obtain two microelectrodes. The resulting microelectrodes display reproducible well-controlled geometry, which is important to downstream quantitative scanning electrochemical studies and imaging. Mechanical polishing of the microelectrode is required and remains the critical step in the fabrication of nanometer size electrodes. Following production, the microelectrodes are characterized by electron microscopy, scanning electrochemical microscopy, and cyclic voltammetry. Development of these microelectrodes is motivated by their subsequent application to electrocatalysis and their potential in theoretical study because of their well-defined geometry. [ABSTRACT FROM AUTHOR]

The fabrication and characterization of novel micropipet probes for use in scanning electrochemical microscopy (SECM) are described. These can be used to dispense small (pL) amounts of a solution while monitoring the electrochemical response at a substrate and at a ring electrode tip on the micropipet probe. The probes were constructed by insulating gold-coated borosilicate micropipets with electrophoretic paint and exposing a ring electrode at the tip by heat treatment. Characterization of the probes was performed using scanning electron microscopy, cyclic voltammetry, and SECM approach curve experiments. Routine construction of tips with diameters of the order of 3 μm was possible using this technique. The probes exhibited stable steady-state currents and positive and negative feedback approach curves that agreed with those predicted by theory. Demonstrative SECM imaging experiments were performed using a picodispenser to continuously dispense an electroactive solution (ferrocenemethanol) to the SECM cell while the probe was located within a few micrometers of a Pt substrate surface. Oxidation of the dispensed electroactive solution was performed at the substrate, and feedback currents were measured at the probe tip by holding the gold ring at a reducing potential. This mode of tip-dispensing SECM was used to obtain images of a platinum substrate electrode while monitoring both the substrate current and the feedback current at the probe. [ABSTRACT FROM AUTHOR]

The present shear-force constant-distance scanning electrochemical microscope regulates tip-to-substrate distance using a phase-controlled feedback mechanism that is more sensitive than the amplitude-controlled constant-distance scanning electrochemical microscopes. Phase control responds faster to frequency perturbation and presents enhance sensitivity during distance curves under constant-distance mode. [ABSTRACT FROM AUTHOR]