Tal Z. Sholklapper

LSM-Infiltrated Solid Oxide Fuel Cell Cathodes

A single-step infiltration method has been developed to incorporate the La 0.85 Sr 0.15 MnO 3-δ (LSM) oxide phase into a pre-sintered, porous yttria-stabilized zirconia (YSZ) network, forming an effective LSM-YSZ composite cathode. The LSM particles, with a size of ∼30 to ∼100 nm, deposit preferentially on the pore walls throughout the porous YSZ, forming a pathway for electron conduction, and creating a high density of active sites for the oxygen reduction reaction. The resulting composite cathode has been evaluated in a solid oxide fuel cell operating at 923 K, and demonstrated the effectiveness of the infiltration process. The single-step infiltration method enables the possibility of producing solid oxide fuel cell cathodes, based on pre-sintered porous YSZ networks, with other catalysts that are not compatible with the high temperature processing that co-firing may require.

Ceria nanocoating for sulfur tolerant Ni-based anodes of solid oxide fuel cells

Conventional nickel yttria-stabilized-zirconia (Ni-YSZ) solid oxide fuel cell anodes infiltrated with ceria nanoparticles showed sustained high sulfur tolerance. Cathode-supported cells with ceria-infiltrated Ni-YSZ anode delivered power density of 220-240 mW cm -2 , at 0.6 V, under an applied current of 0.4 A cm -2 , when operating on humidified H 2 fuel containing 40 ppm H 2 S, at 973 K, for 500 h. In contrast, the power density of a cell with traditional Ni-YSZ anode dropped to near 0 mW cm -2 , in ∼ 13 min, when similarly exposed. The results indicate that ceria nanoparticle infiltration can effectively increase the sulfur tolerance of conventional Ni-YSZ anodes.

LSM-YSZ Cathodes with Reaction-Infiltrated Nanoparticles

To improve the LSM-YSZ cathode performance of intermediate temperature solid oxide fuel cells (SOFCs), Sm0.6Sr0.4CoO3-sigma (SSC) perovskite nanoparticles are incorporated into the cathodes by a reaction-infiltration process. The SSC particles are {approx}20 to 80nm in diameter, and intimately adhere to the pore walls of the preformed LSM-YSZ cathodes. The SSC particles dramatically enhance single-cell performance with a 97 percent H2+3 percent H2O fuel, between 600 C and 800 C. Consideration of a simplified TPB (triple phase boundary) reaction geometry indicates that the enhancement may be attributed to the high electrocatalytic activity of SSC for electrochemical reduction of oxygen in a region that can be located a small distance away from the strict triple phase boundaries. The implication of this work for developing high-performance electrodes is also discussed.

Real-time materials evolution visualized within intact cycling alkaline batteries

The scientific community has focused on the problem of inexpensive, safe, and sustainable large-scale electrical energy storage, which is needed for a number of emerging societal reasons such as stabilizing intermittent renewables-based generation like solar and wind power. The materials used for large-scale storage will need to be low cost, earth-abundant, and safe at the desired scale. The Zn–MnO2 “alkaline” battery chemistry is associated with one-time use, despite being rechargeable. This is due to material irreversibilities that can be triggered in either the anode or cathode. However, as Zn and MnO2 have high energy density and low cost, they are economically attractive even at limited depth of discharge. As received, a standard bobbin-type alkaline cell costs roughly

The relationship between coefficient of restitution and state of charge of zinc alkaline primary LR6 batteries

20 per kW h. The U.S. Department of Energy ARPA-E

Synthesis of Dispersed and Contiguous Nanoparticles in Solid Oxide Fuel Cell Electrodes

100 per kW h cost target for grid storage is thus close to the cost of alkaline consumer primary cells if re-engineered and/or cycled at 5–20% nominal capacity. Herein we use a deeply-penetrating in situ technique to observe ZnO precipitation near the separator in an alkaline cell anode cycled at 5% DOD, which is consistent with cell failures observed at high cycle life. Alkaline cells designed to avoid such causes of cell failure could serve as a low-cost baseload for large-scale storage.

Nanocomposite Ag-LSM solid oxide fuel cell electrodes

The coefficient of restitution of alkaline batteries has been shown to increase as a function of depth of discharge. In this work, using non-destructive mechanical testing, the change in coefficient of restitution is compared to in situ energy-dispersive X-ray diffraction data to determine the cause of the macroscopic change in coefficient of restitution. The increase in coefficient of restitution correlates to the formation of a percolation pathway of ZnO within the anode of the cell, and the coefficient of restitution levels off at a value of 0.66 ± 0.02 at 50% state of charge when the anode has densified into porous ZnO solid. Of note is the sensitivity of coefficient of restitution to the amount of ZnO formation that rivals the sensitivity of in situ energy-dispersive X-ray diffraction.