Activity of layered swedenborgite structured Y_0.8Er_0.2BaCo_3.2Ga_0.8O_7+δ for oxygen electrode reactions in at intermediate temperature reversible ceramic cells

Abstract

A new class of layered swedenborgite structured Y0.8Er0.2BaCo3.2Ga0.8O7+δ is proposed for oxygen electrode reactions in reversible ceramic cells because of its low thermal expansion and high chemical bulk diffusion coefficients.

Utilizing the Intrinsic Thermal Instability of Swedenborgite Structured YBaCo4O7+δ as an Opportunity for Material Engineering in Lithium-Ion Batteries by Er and Ga Co-Doping Processes

“…Likewise, the Co ions in BaCoO 3 (marked as gray-colored symbols in the figure), which is a main decomposition product of YBC, have octahedral coordination [27], whereas the Co ions in YBC have a tetrahedral coordination. Meanwhile, Table 1 lists the crystal lattice parameters of pristine YBC and YEBCG, showing the increased lattice parameters of a-and c-axes with larger lattice volume for YEBCG compared to YBC, which is consistent with the previous literature [22]. To elucidate the relationship between changes in structural phase and morphology before and after the Li-intercalation process, a FE-SEM analysis was performed.…”

“…) 2 Ce(NO 3 ) 6 (99.99%, Alfa Aesar), and Ga(NO 3 ) 3 •xH 2 O (99.9%, metal basis, Alfa Aesar) were dissolved in distilled water with glycine as a combusting fuel and then heated on a heating plate (MSH-20D, DAIHAN Scientific Co., Ltd., Wonju, Korea) at 350 • C until the metal nitrates converted into black ashes. After the combustion, the ashes were ground with a mortar and then calcined at 1000 • C for 12 h under an air atmosphere to obtain a single-phased crystalline [22]. In order to identify the crystal structure of the YBC-based materials, an X-ray diffraction (XRD) technique (X'Pert, PANalytical, Cu Kα radiation, Almelo, The Netherlands) was carried out with a step size of 0.026 • in a 2θ range from 10 to 80 • .…”

“…Manthiram et al reported that YBC doped with the optimum content of Ga, which substitutes for Co sites, can effectively overcome this phase instability at high temperatures of 600-800 • C [21]. Our recent work reported that Er and Ga co-doped YBC oxide (YEBCG) showed excellent phase stability compared to YBC, presenting long-term durability under reversible protonic ceramic cell conditions [22]. Meanwhile, there are a few reports adopting Er or Ga as dopants for cathode-active materials in LIBs.…”

Highly Active and Durable Air Electrodes for Reversible Protonic Ceramic Electrochemical Cells Enabled by an Efficient Bifunctional Catalyst

“…[1][2][3] A central goal of current research on SOCs is to reduce the working temperatures to intermediate-to-low temperatures (500-700 °C) for the purpose of improving thermal cycling tolerance, facilitating dynamic response, and reducing the system costs. [4][5][6] In particular, the reversible protonic ceramic electrochemical cells (R-PCECs) operated at reduced temperatures have attracted much attention in recent years because of their excellent performance (due to the low activation energies for proton transport) as well as the production of pure and dry H 2 in the electrolysis mode. [7][8][9][10] To make R-PCECs commercially competitive at intermediate-to-low temperatures, one of the main priorities is to develop air electrodes with high electrocatalytic activity and stability.…”

“…[8,11,12] However, the kinetics of oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) at the air electrode decreases exponentially as the working temperature is reduced, significantly increasing the polarization resistance (R p ) of the R-PCECs. [6,13,14] In addition, at the air electrode of an R-PCEC, a large amount of water is generated in the fuel cell mode and consumed in the electrolysis mode, further exacerbating the polarization losses and poor stability of the air electrode. Since water is generated and consumed at the fuel electrode, not the air electrode, of the SOCs based on an oxygen ion conducting electrolyte (O-SOCs), [15] most air electrodes designed for O-SOCs may not be suitable for R-PCECs due to the insufficient catalytic activity and stability in high concentration of water at low temperatures.…”