Evaluation of La1.8−xPrxSr0.2CuO4−δ oxides as cathode materials for IT-SOFCs

Development of novel air electrode materials for the SOFC and SOEC technologies

“…Interesting electrochemical performance, SOFC output 0.16 W cm -2 at 800 °C with LSGM (lanthanum gallate doped with strontium and magnesium) as electrolyte, was reported for Sr-doped La2CuO4 [82]. Moreover, Kolchina et al, as well as Li et al presented its longterm chemical stability with CGO electrolyte and one of the lowest for cuprates ASR values (0.16 Ω cm 2 ) and the lowest cathodic overpotential equal 100 mV at the current density of 150 mA cm -2 at 700 °C [85,86]. Similarly to the perovskite cuprates, so far no data on the layered Ln2CuO4±δ tested in the SOEC mode are available.…”

Recent advances, practical challenges, and perspectives of intermediate temperature solid oxide fuel cell cathodes

“…Layered K 2 NiF 4 -type Ln 2 NiO 4+ δ (Ln = La, Pr, Nd) nickelates and cuprates have garnered interest for exhibiting high oxygen ion diffusivity, 195,243 surface exchange kinetics, sufficient electrical conductivity 244 and moderate thermal expansion coefficients, 245–247 earning them a space amongst promising alternative IT-SOFC cathode materials. For example, Boehm et al demonstrated higher oxygen bulk diffusion ( D * ∼ 4.15 × 10 −7 cm 2 S −1 ) and surface exchange coefficient ( k * ∼ 7.57 × 10 −6 cm S −1 ) in RP Ln 2 NiO 4+ δ nickelates than conventional La 0.6 Sr 0.4 Fe 0.8 Co 0.2 O 3− δ ( D * ∼ 5.40 × 10 −9 cm S −1 , k * ∼ 9.26 × 10 −8 cm S −1 ) at 700 °C.…”

Mechanism for the Enhancement of the Oxygen Diffusivity by Cation Substitution in La2–xSrxCuO4

“…It has been recently reported that Ruddlesden–Popper (RP) oxides Ln 2 MO 4 , in which Ln denotes a lanthanide element such as La, Pr, Nd, or Sm, and M denotes a light late transition metal such as Mn, Mn, Fe, Co, Ni, or Cu, can be promising candidates for the cathode material, due to their fast oxygen reduction reaction kinetics, − higher oxygen diffusivity than most perovskite-based oxides, , compatible thermal expansion coefficients with current electrolytes, high chemical stability against oxygen non-stoichiometry, and oxygen partial pressure gradient . Among these properties, their sufficiently high oxygen diffusivity is regarded as a key feature of RP oxides for their intermediate-temperature operation. , In Ln 2 MO 4 , oxygen vacancies and interstitials play major roles in oxygen-deficient and oxygen-excessive conditions, respectively, but the underlying atomic processes are usually difficult to identify experimentally.…”