Nanotemplated platinum fuel cell catalysts and copper-tin lithium battery anode materials for microenergy devices

Nanotemplated materials have significant potential for applications in energy conversion and storage devices due to their unique physical properties. Nanostructured materials provide additional electrode surface area beneficial for energy conversion or storage applications with short path lengths for electronic and ionic transport and thus the possibility of higher reaction rates. We report on the use of controlled growth of metal and alloy electrodeposited templated nanostructures for energy applications. Anodic aluminium oxide templates fabricated on Si for energy materials integration with electronic devices and their use for fuel cell and battery materials deposition is discussed. Nanostructured Pt anode catalysts for methanol fuel cells are shown. Templated CuSn alloy anodes that possess high capacity retention with cycling for lithium microbattery integration are also presented

Porous alumina thin films on conductive substrates for templated 1-dimensional nanostructuring

The growth of thin porous anodic aluminum oxide (AAO) films on silicon by anodizing Al on Ti/Au/Si and Ti/Pt/Si substrates in oxalic acid was demonstrated. Removal of the Al2O3 barrier layer was effected by selective chemical etching in H3PO4 and a reversed bias method in the anodizing solution. Ion transport and the influence of the Ti adhesion layer at the oxide–metal interface during the critical stages of anodization and pore opening were investigated. The AAO films may be exploited as templates in the creation of silicon-integrated nanostructured wire arrays. Electrodeposition of Pt into the AAO template yielded a nanowire array with superior methanol oxidation activity that can be integrated in a micro direct methanol fuel cell

Anion Exchange Membrane Capacitive Deionization Cells

The electrochemical response of capacitive deionization (CDI) employing a single anion exchange membrane (AEM-CDI) is contrasted to conventional two-membrane CDI (MCDI) formed with complementary anion and cation exchange membranes. Pristine activated carbon cloth electrodes that possess native positive surface charge in solution were used as both anode (positive electrode) and cathode (negative electrode) in these cells. In a separate set of tests to investigate the impact of surface charge modification on deionization responses, the single and dual membrane cells were formed with asymmetric electrodes (AEM-aCDI and aMCDI) consisting of nitric acid oxidized electrodes that possess negative surface charge as the cathode material, while pristine carbon cloth was retained as the anode material. Operating at 1.2 V, salt adsorption capacities are ∼1.3, 9.9, and 16.6, and 17.3 mg NaCl g−1 electrode for the AEM-CDI, MCDI, AEM-aCDI, and aMCDI, respectively. The diminished performance of AEM-CDI is attributed to charge expulsion and enhanced parasitic electrochemical reactions at the unprotected cathode that reduce the charge efficiency. In contrast, for AEM-aCDI, a treated cathode enhances surface charge effects to match aMCDI performance with half the membrane requirement

Low Temperature Liquid Metal Batteries for Energy Storage Applications

The present invention relates to a molten metal battery of liquid bismuth and liquid tin electrodes and a eutectic electrolyte. The electrodes may be coaxial and coplanar. The eutectic electrolyte may be in contact with a surface of each electrode. The eutectic electrolyte may comprise ZnC12:KCI

Method for Energy Storage to Utilize Intermittent Renewable Energy and Low-Value Electricity for CO\u3csub\u3e2\u3c/sub\u3e Capture and Utilization

A power plant includes a boiler, a steam turbine, a generator driven by that steam turbine, a condenser, a post combustion processing system and an energy storage system including at least one electrochemical cell to store excess electrical energy generated by the generator during period valley demand and release thermal energy for power plant operations at other times

Activated carbon as a redox flow battery

With the increase of renewable wind and solar energy, there is a need for long-term, low-cost energy storage systems to buffer their variable output. Redox flow batteries (RFBs) have the potential to store large amounts of energy for on-demand power generation and long-duration discharge. RFBs consist of two soluble redox couples stored in separate tanks that are flowed through a stack during charge/discharge, decoupling the battery’s power and energy capacity to meet custom scaling requirements. Despite this flexibility, RFBs currently have low energy densities compared to rechargeable lithium-ion batteries due to poor aqueous solubility of the active species and/or low voltage outputs. Robust, high voltage catholytes are needed in RFBs. The catholyte iron (II/III) tris-2,2’-bipyridine

Improvements in aqueous redox flow batteries employing low cost and sustainable TEMPO-OH catholyte

Solar and wind energy generation and their grid-scale integration are growing rapidly, however their efficient utilization is impeded by the intrinsic intermittency of these renewable energy sources. Aqueous organic redox flow batteries (AORFBs) employing synthetically tailorable organic electroactive compounds composed of earth-abundant elements have received significant attention for energy storage technologies for their low cost, safety, and tunable properties. A redox flow battery (RFB) stores its energy in redox-active materials dissolved in liquid electrolytes circulating between external reservoirs and the battery stack, gives rise to their main advantages of decoupled energy and power, and excellent scalability. Regardless of this, they are facing daunting challenges such as low utilization ratio, high system complexity, low solubility, insufficient lifetimes, and scale-up difficulties. Therefore, to achieve high-energy-density flow batteries, electrolytes with electroactive materials that have high concentrations, high redox potentials, and ultra-low-capacity fade need to be developed. The nitroxyl radical 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (4-HO-TEMPO) and its derivatives has been evaluated as a cost-effective catholyte for AORFBs in pH-neutral supporting electrolytes. TEMPO compounds can operate at high current density (up to 100 mA cm−2) and deliver impressive cycling performance due to its considerable positive redox potential. However, imperfect chemical stability and capacity decay, which are exacerbated at high concentrations, are still unacceptably high for TEMPO species. The presented research highlights the possibility to enhance the longevity of (4-HO-TEMPO) at high concentrations when paired with 1,10-bis(3-sulfonatopropyl)-4,4 -bipyridinium (SPr)2V anolyte. Moreover, this research is focused specifically how pH impacts redox reversibility, diffusion coefficient and kinetic rate constant by inducing or suppressing disproportionation of TEMPO and other side reactions. Herein we build upon recent progress with this promising catholyte species and improve performance by using buffers to maintain the pH of electrolytes to avoid degradation and thus high-capacity fade rates of TEMPO

Improving the voltage and lifetime in aqueous redox flow batteries utilizing the organometallic [Fe(bpy)3]2+/3+

Department of Physical and Environmental Sciences, College of ScienceLong term battery storage is needed for renewable energy sources to buffer their variable output. Redox flow batteries (RFBs) have the potential to store large amounts of energy for on-demand power generation. Current issue: low energy density due to poor solubility of the active species and low voltage outputs. Robust, high voltage catholytes are needed. Iron (II/III) tris-2,2’-bipyridine ([Fe(bpy)3]2+/3+) is a suitable catholyte. This work introduces a new way to synthesize [Fe(bpy)3]2+ and methods to improve performance.This research was supported by funding from The Welch Foundation. Dr. Mark Olson – Chemistry Program Coordinato

Nanotemplated platinum fuel cell catalysts and copper-tin lithium battery anode materials for microenergy devices

Nanotemplated materials have significant potential for applications in energy conversion and storage devices due to their unique physical properties. Nanostructured materials provide additional electrode surface area beneficial for energy conversion or storage applications with short path lengths for electronic and ionic transport and thus the possibility of higher reaction rates. We report on the use of controlled growth of metal and alloy electrodeposited templated nanostructures for energy applications. Anodic aluminium oxide templates fabricated on Si for energy materials integration with electronic devices and their use for fuel cell and battery materials deposition is discussed. Nanostructured Pt anode catalysts for methanol fuel cells are shown. Templated CuSn alloy anodes that possess high capacity retention with cycling for lithium microbattery integration are also presented