Rational design of an in-situ co-assembly nanocomposite cathode La0.5Sr1.5MnO4+δ-La0.5Sr0.5MnO3-δ for lower-temperature proton-conducting solid oxide fuel cells

In response to the exigent topic of exploiting low cost high active electrode materials for proton-conducting solid oxide fuel cells (H–SOFC), a novel strategy using K2NiF4-type layered La0.5Sr1.5MnO4+δ (LSMO4) with interstitial oxygen transfer mode as ionically conductive phase for La1-xSrxMnO3-based cathodes is proposed. With the adoption of one-step in-situ co-assembly method, the 20–40 nm dual-phase equimolar nanocomposite LSMO4-La0.5Sr0.5MnO3-δ (LSMO4-LSM) is obtained at 1000 °C, corroborated by the XRD and TEM results. When assembled with the BZCY electrolyte, the LSMO4-LSM cathode possesses much lower area specific polarization resistances in symmetrical cells and better electrochemical performance in single cells than that of the LSM cathode. Correspondingly, the electrode process is changed with the introduction of LSMO4 and an excellent cell performance with the peak power density (PPD) of 936 mW cm−2 and the interfacial polarization resistance (RP) of 0.082 Ω cm2 at 700 °C is attained, respectively. On the whole, the extremely tiny particles and competitive cell performance with LSMO4-LSM cathode could illustrate the superiority of the in-situ co-assembly technique combined with the novel strategy, providing new ideas or methods for designing high performance H–SOFC electrode materials.