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Development of Room-Temperature Ionic Liquids for Reversible Electroplating


TECHNOLOGY AREA(S): Materials/Processes

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 5.4.c.(8) of the solicitation and within the AF Component-specific instructions. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. Please direct questions to the AF SBIR/STTR Contracting Officer, Ms. Gail Nyikon,

OBJECTIVE: Create room-temperature ionic liquids that are robust, non-volatile, transparent, rad hard, and atmospherically tolerant for use in electrolytes for reversibly electroplating films with specific optical, emissive and electrical properties on demand.

DESCRIPTION: This topic seeks to engage small businesses and academia to create robust, non-volatile, transparent, radiation-hardened, and atmospherically tolerant room-temperature ionic liquids for use in electrolytes for running reversible electroplating reactions that can establish and remove metallic films with specific optical, emissive, and electrical properties by tailoring the structure and thickness of the electrodeposited layer through modulation of the applied voltage at the working electrode. Such liquids are of interest since their properties could allow reversible electroplating techniques, capable of tuning or regenerating functional surfaces, to be deployed on orbital platforms. This can allow for in-flight modification of functional surfaces, such as mirrors or thermal emitters, to meet new operational needs or the restoration of functional surfaces if they are ever damaged.

Developing room-temperature ionic liquids with the aforementioned properties is the focus of this topic since the unique characteristics of ionic liquids suggest they can be used to make effective space compatible electrolytes and the properties sought are needed to support applications of interest. The negligible volatility of ionic liquids means they will not evaporate if exposed to the vacuum of space and their robustness suggest they can tolerate exposure to orbital radiation and provide large electrochemical windows to drive electrochemical reactions. Atmospheric tolerance is sought since this simplifies handling requirements and transparency is sought to allow the capabilities provided by the ionic liquids to be used in areas within a field of view of an optical application.

Work sought in this topic will focus on creating new room-temperature ionic liquids with the following nine properties. First, ionic liquids created in this effort will be capable of solvating metal ions. Of particular interest is the solvation of metals capable of forming highly reflective mirrors such as silver, aluminum, tin, copper, and gold. Second, the liquids developed will be suitable for use as the solvent in an electrolyte solution which can be used to run reversible electroplating reactions. Third, reversible electroplating reactions run in solutions created with these ionic liquids will be capable of reliably generating and removing highly reflective metallic mirrors. Fourth, the liquids developed will allow mirrors to be electroplated and removed at least 100 times, ideally over 100,000 times, without degrading common transparent electrically conductive electrodes, such as indium tin oxide doped glass. Fifth, electroplating reactions run with these liquids will allow the generation of mirrors with consistent properties on demand. Sixth, the liquids created will be capable of accommodating high metal ion migration rates so that any process to form or remove mirrors can complete quickly. Seventh, the liquids created will be capable of withstanding extended exposure to the Earth’s atmosphere. Eighth, the liquids developed will be able to tolerate exposure to hostile conditions found in an orbital environment. Ninth, the room-temperature ionic liquids created in this effort will be reasonably transparent over a broad spectrum of light. The wavelengths of light where it is particularly desirable for the ionic liquid to be transparent are those in the visible and infrared spectrum.

While a proposer for this topic must have the resources to complete the proposed work independently, access to governmental laboratory facilities will be available to help verify synthetic procedures, characterize molecules, evaluate electrochemical performance, assess electrodeposited layers, and check radiation tolerance as necessary in consultation with the government.

PHASE I: Synthesize novel room-temperature ionic liquids that are reasonably transparent across broad spectrums of light and can be used to create electrolyte solutions from which highly reflective mirrors can be generated and removed via reversible electrodeposition. Ideally these liquids will be non-toxic, robust, atmospherically stable, and tolerant of hostile conditions found in an orbital environment.

PHASE II: Quantify the robustness of ionic liquids created in Phase I against exposure to the Earth’s atmosphere, determine the stability of the ionic liquids after repeated reversible electroplating cycles, assess the consistency in the properties of mirrors generated via electroplating, evaluate the extent to which the liquids can tolerate hostile conditions found in an orbital environment, and enhance desired properties by modifying the structure of the ionic liquids or dissolving chemicals into them.

PHASE III DUAL USE APPLICATIONS: Transition the room-temperature ionic liquids created in this work into commercial products for use as non-volatile solvents, components in electrolyte solutions for electrochemical processes, or novel catalysts which work by holding molecules in reactive orientations.


    • Abbott, A. P. et. al., Electroplating Using Ionic Liquids. Annual Review of Materials Research 2013, 43, 335-358.


    • Araki S., et. al., Electrochemical Optical-Modulation Device with Reversible Transformation Between Transparent, Mirror, and Black. Advanced Materials 2012, 24 (23), OP122-OP126.


    • Hallett, J. P., et. al., Room-Temperature Ionic Liquids: Solvents for Synthesis and Catalysis. 2. Chemical Reviews 2011, 111 (5), 3508-3576.


    • He, P., et. al., Electrochemical Deposition of Silver in Room-Temperature Ionic Liquids and Its Surface-Enhanced Raman Scattering Effect. Langmuir 2004, 20 (23), 10260-10267.


  • Giridhar P., et. al., “Electrodeposition of aluminium from 1-butyl-1-methylpyrrolidinium chloride/AlCl3 and mixtures with 1-ethyl-3-methylimidazolium chloride/AlCl3”, Electrochimica Acta 2012, 70, 210-214.

KEYWORDS: ionic liquid, electrolyte, chemistry, reversible, electroplating, electrodeposition, electrochemistry, mirror, synthesis, spacecraft, space, room temperature ionic liquid

  • TPOC-1: Thomas Peng
  • Phone: 505-846-4524
  • Email:
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