A new highly active and CO2-stable perovskite-type cathode material for solid oxide fuel cells developed from A- and B-site cation synergy

Abstract

Improving the activity of a cathode material towards the oxygen reduction reaction (ORR) and its tolerance against CO2 impurities is of prime importance to realizing the application of solid oxide fuel cells that operate under intermediate temperatures (IT-SOFCs). Here, by adopting an A- and B-site co-doping strategy, we report a new perovskite-type oxide, Nd0.2Sr0.8Nb0.1Co0.9O3-δ (N0.2SNC), as an active and CO2-tolerant cathode material for IT-SOFCs. Compared with single-site doped Nd0.2Sr0.8CoO3-δ (N0.2SC, A-site doping) and SrNb0.1Co0.9O3-δ (SNC, B-site doping) and the parent oxide SrCoO3-δ (SC), N0.2SNC shows improved electrocatalytic activity for the ORR and superior resistance towards CO2 poisoning, achieving a low area specific resistance (ASR) of 0.037 Ω cm2 at 650 °C. In addition, the ASR value of the N0.2SNC electrode only increases from 0.08 to 0.20 Ω cm2 after operating for 300 min under an air atmosphere with 5% CO2. A- and B-site cation synergy is obtained through co-doping, leading to the improved performance. A peak power density of 1563 mW cm−2 is achieved at 650 °C. This A- and B-site cation synergy may offer a new avenue for developing high-performance and CO2-stable cathode materials for IT-SOFCs.