In Situ Characterization of Electrochemical Processes - Cypher™ ES

The Electrochemistry Cell for the Asylum Research Cypher ES AFM is the premier solution for in situ AFM characterization of electrochemical (EC) processes. Its simple modular design offers great versatiliy and compatibility with a broad range of materials. Moreover, it is based on the Cypher ES AFM — the world’s highest-resolution, fast-scanning AFM with greater environmental control and ease of use for maximum productivity.

Time series of AFM images

Time series of AFM images showing the electrochemical stripping of copper from a gold electrode in an acidic 0.1 M copper sulfate solution, 2 μm scans. Imaged in tapping mode using blueDrive™ photothermal excitation. Graph: Voltammogram showing reductive deposition and oxidative stripping corresponding to the process shown in the images.

The Highest Performance Electrochemical AFM

  • Completely sealed EC cell with uniquely-designed probe holder and liquid cup for easy imaging in fluid
  • Simple to clean and assemble, even with gloves
  • Compatible with most common solvents, electrolytes and electrode materials
  • Glovebox option offers the ultimate environmental control without any performance compromises
  • Optional cooling and heating stages allow examination of electrochemical thermodynamics

Designed for the Rigors of EC Research

  • The EC Cell liquid cup features a ~200 μL working volume — large enough to avoid significant reaction induced concentration variations and small enough to conserve reagents — and prevents low surface tension liquids from leaking.
  • Sample chamber prevents electrolyte evaporation and offers secondary containment against spills.
  • Quartz-constructed probe holder dips the AFM probe and the reference electrode into the liquid volume.
  • The liquid cup forms a well-defined working electrode surface area, ~55 mm2, enabling quantitative electrochemistry and eliminating electric field edge effects.
  • The EC Cell liquid cup and probe clip are provided in both glass-filled PEEK and PPS (Ryton®) for compatibility with a majority of solvent electrolyte materials. A perfluoroelastomer O-ring (FFKM, P-Rex®) seals against the working electrode.
  • Ring-shaped counter electrode avoids directional artifacts.
  • Shielded electrode connections preserve extremely sensitive signals and route neatly to an external potentiostat.
  • Optional glovebox integration for the ultimae sub-ppm control of oxygen and water levels.

EC Cell liquid cup and sample stage

EC Cell liquid cup and sample stage

Partial bottom view of the EC probe holder

Partial bottom view of the EC probe holder

Experimental Versatility and Simplest User Experience

  • Optional cooling and heating stages allow investigation of electrochemical thermodynamics.
  • Two gas ports and two optional liquid perfusion ports enable trouble-free gas and electrolyte exchange
  • Connect to your choice of commercial potentiostats, or Asylum Research can recommend a suitable general-purpose model
  • Modular counter and reference electrodes allow users to select the most appropriate materials
  • EC Cell is compatible with square and round samples, diameters from 9 to 15 mm
  • All components are rapid and simple to clean and assemble, even wearing gloves

the Cypher EC cell

Applications

  • Characterizing energy storage materials under bias, such as membranes, battery electrodes and solution-electrode interfaces
  • Examining kinetics of corrosion
  • Electrodeposition and stripping of metals
  • Nucleation and growth of nanoparticles
  • Monitoring morphology over time of microorganisms, electrode-attached biocatalysts and other biophysical research

Aqueous cyclic voltammetry

Aqueous cyclic voltammetry

Aqueous cyclic voltammetry of 1 mM ferro-/ferricyanide in 100 mM KCl with a Au-sputtered mica working electrode (WE). Each colored trace represents two scan cycles and shows the one-electron process [Fe(CN)6 ]4− ⇌ [Fe(CN)6 ]3− + e−. (Top) Current response as a function of temperature, T, at a scan rate of 100 mV/s. Inset shows Arrhenius-type behavior with an activation energy of 0.17 eV (16.6 kJ/mol). Temperature is controlled in the Cypher ES sample chamber with the Heater or HeaterCooler stages. (Bottom) Current response as a function of scan rate, ν, at ambient temperature (29 °C). The potentiostat may be used to vary ν over many orders of magnitude. Inset plots show the scan rate dependence of peak potential (Epeak ) and peak current amplitude (ipeak).

Electrochemical research will benefit from these core Cypher capabilities

Highest-resolution imaging Cypher makes high-resolution imaging straightforward. No other AFM makes real atomic resolution routine!

Atomic point defect

Atomic point defect in calcite imaged in the Cypher EC Cell in tapping mode using blueDrive, 5 nm scan.

blueDrive photothermal excitation blueDrive is simply a better way to tap — blueDrive tunes are stable and clean, and closely match the theoretical reaction. There is never a “forest of peaks” like those seen when using piezo drive for tapping in liquid. You can image for hours without adjusting the setpoint. blueDrive also enables tapping mode operation in extremely viscous media like ionic liquids.

Titanium dioxide

Titanium dioxide substrate imaged in a highly viscous liquid using tapping mode with blueDrive, 5 μm scan.

Excellent top-view bright-field optics Cypher features diffraction-limited top- view optics that achieve <1 μm resolution. Modifiable aperture and field diaphragms help improve contrast on challenging samples.

surface deposition of copper on gold

Optical images through the top-view optics showing surface deposition of copper on gold over time. The probe is an AC40 cantilever, (40 μm long).

Specifications

The Electrochemistry Cell is available in a full kit that includes the EC probe holder, EC liquid cup, EC sample holder and standard electrodes.

Requirements

  • Cypher ES AFM scanner The EC Cell is engineered for environmental control with easy assembly.
  • Potentiostat Customer preference of brand. CH Instruments 630E model may be bought from Asylum Research.
  • blueDrive photothermal excitation Allows for tapping mode (AC) imaging. Note there is no tapping piezo on the EC Cell probe holder.

EC Cell Liquid Cup

Makes contact with electrolyte

  • Electrolyte containment cup Glass-filled PPS or PEEK, both provided. Working volume with probe holder completely engaged is 150-250 μL.
  • O-ring seal to working electrode FFKM perfluoroelastomer. 8.4 mm ID sets working electrode active area to ~55 mm2 for quantitative analyzes. Edges and sides of sample are not exposed to liquid.
  • Counter electrode Copper; concentric design; 12.7 mm OD 9.5 mm ID, and 0.13 mm thick, for a two-sided total surface area of ~120 mm2. Pt version available as an option. Note: Customer can easily form electrode from metal wire of their choice.
  • Sample (working electrode) Customer preference; 9-15 mm circular diameter or square range, but with an exposed area of ~55 mm2 at all times. Sample substrate can be insulating or conducting with a thickness range from 0.5-2.0 mm.

EC Probe Holder

Makes contact with electrolyte

  • Probe support and optical window Fused silica (quartz) downtube probe support and optical window; 5 mm OD; 5 mm dipping height.
  • O-ring seal to sample chamber FFKM perfluoroelastomer; 8.4 mm ID. 0.8 mm cross section diameter.
  • Probe clip Glass-filled PEEK or PPS; 7.0 mm OD; 5.0 mm ID. Both included.
  • Reference electrode wire Ag wire comes standard; customer preference. Sealed with FFKM O-ring or PTFE (Teflon®) tape. Feedthrough hole 1.0 mm in diameter.
  • Optional with two liquid perfusion ports Compatible with FEP tubing, 0.8 mm OD, 0.4 mm ID.

Note: No adhesives contact electrolyte

Cypher ES Sample Chamber

Does not come into direct contact with the electrolyte. Makes contact with chamber atmosphere.

  • Chamber wall Fused silica; 25.4 mm ID with three metal rust-proof magnetic nickel contacts for working, ground and counter electrode connections. Humidity sensor (optional).
  • Gas perfusion/exchange ports FEP; 1.6 mm OD, 0.8 mm ID
  • Bellows For emergency liquid containment and mechanically adaptive atmosphere isolation. FFKM perfluoroelastomer.
  • Chassis Nickel plated Invar® metal. Chassis does not touch the liquid

Note: Chamber is not meant to be filled with liquid.

Compatible with Common Electrolyte Solvents

  • Aqueous salt solutions and buffers (for example KCl, phosphate buffered saline, HEPES)
  • Halogenated solvents (for example chloroform, chlorobenzene)
  • Organic solvents (for example toluene, THF, dimethoxyethane)
  • Organic amines (for example ethylenediamine)
  • Organic carbonates (for example propylene carbonate, ethylene carbonate)
  • Caustics (for example HCl, NaOH). Note: HF will etch the quartz
  • Ionic liquids (for example imidazolium/pyridinium/substituted-ammonium cations with NTf2/ PF6/halide anions)

Operating Modes Available with the EC Cell

AM-FM Viscoelastic Mapping; Contact; Contact Resonance Viscoelastic Mapping; Dual AC; Dual AC Resonance Tracking (DART); Force Mapping (Force Volume); Force Modulation; Fast Force Mapping (FFM); Frequency Modulation; Loss Tangent Imaging; Magnetic Force Microscopy (MFM); Lateral Force (LFM); Nanolithography and Nanomanipulation; Phase Imaging; Tapping Mode (AC Mode); Tapping with digital Q control.

Note: The EC Cell probe holder is entirely functional for non-EC imaging in air or liquid. For some applications, its dipping-style architecture may be ideal compared to other Cypher probe holders.

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