The electrical double layer (EDL) of ionic liquids (ILs) near electrified surfaces do not follow classical theories such as Helmholtz, Gouy-Chapman and Stern. We investigate IL EDL utilizing advanced spectroscopy and scattering techniques, coupled with electrochemical methods. In particular, the accessibility and wettability of ionic liquid ions in EDL capacitors that utilize high surface area porous electrodes are of interest for high performance energy storage devices. We design and synthesize ILs to better develop the structure-property relations that govern the electrode-electrolyte interfaces. We are also interested in charge transfer properties at these interfaces for battery and electrocatalysis applications.
* * *
Ionic Liquids for Safer Batteries
Ionic liquids are inherently nonflammable and have negligible vapor pressures; thus are safer alternatives over organic solvents for lithium, lithium-ion and sodium-ion batteries where aqueous electrolytes are not suitable.
We observe unique capabilities with ILs in lithium batteries where the lithium deposition is more uniform compared to organic electrolytes. This is attributed to the stable solid-electrolyte interface (SEI) that is formed on the lithium metal surface. Understanding the SEI formation in ILs is a complex task. We investigate the underlying mechanism that leads to enhanced battery cycle life.
The outcome of this study is pertinent to lithium-sulfur batteries where the lithium metal is ideally used as the anode.
* * *
Design and Synthesis of Carbonaceous Porous Materials
High surface area carbon materials are used in applications such as supercapacitors, absorbents, and heterogenous catalyst supports. The most adapted route in the synthesis of well-structured mesoporous carbons is the evaporation induced self-assembly of carbon precursors around the amphiphilic block copolymer in the case of soft-templating and inorganic master in hard-templating. This process impose health hazards from direct handling, burning and post-removal since it relies on the evaporation of volatile solvents which imposes additional environmental concerns and a regulated atmosphere to adapt to large-scale manufacturing. We are working on developing an alternative method that is greener and where the nonvolatile, natural and multi-purpose ingredients are used. We are interested in the application of these materials as electrodes in energy storage devices and as supports for the capture and conversion of carbon dioxide.
* * *
Electrochemical Reduction of Carbon Dioxide
The electrochemical reduction of carbon dioxide is the 146-year-old, still an unresolved, challenge that was first studied in 1870 by M. E. Royer in Paris. It was considered that the only significant products in aqueous solutions were formic acid (HCOOH) and formates (HCOO-) of alkali metals with the highest current densities (> 90 %) achievable with mercury or amalgam (alloys of mercury and metals) electrodes. Despite the progress thereafter, the process still requires to be optimized for selectivity and efficiency.
CO2 is a cheap carbon source and available as waste from fossil fuel burning processes. We combine the electro reduction process to simultaneously capture and convert the carbon dioxide to higher value products.