Exceptional High-Performance Oxygen Transport Membrane and Comprehensive Study on Mass/Charge Transport Properties

Abstract

This study focuses on mixed-conducting perovskite membranes for efficient oxygen supply, aiming to replace energy-intensive cryogenic distillation with a more practical alternative. A La and Nb co-doped BaCoO_3−δ perovskite is introduced, Ba_0.95La_0.05Co_0.8Fe_0.12Nb_0.08O_3−δ (BLCFN) with a record-breaking oxygen permeation flux, surpassing all known single-phase perovskite membranes. To elucidate its superior membrane performance, the mass/charge transport properties and equilibrium bulk properties are investigated and quantitative indicators (D_O = 5.8 × 10⁻⁶ cm² s⁻¹, k_O = 1.0 × 10⁻⁴ cm s⁻¹, σ_ion = 0.93 S cm⁻¹ at 900 °C) reveal fast diffusion and excellent surface gas-exchange kinetics. The oxygen permeability of 12.4 mL cm⁻² min⁻¹ and over 200 h of long-term stability is achieved in an air/He atmosphere at 900 °C. By presenting a material that demonstrates higher performance than Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCF), currently known for its highest permeability, it is believed that this marks a significant step toward innovative performance enhancement of perovskite oxide-based membranes.