Monolithic gyroidal solid oxide cells by additive manufacturing

Solid oxide cells (SOCs) efficiently interconvert chemicals and electricity. However, they are primarily confined to 2D design and fabrication technologies. Planar SOC stacks require complex multi-material components, leading to reduced compactness and high specific weight. Here we escape the 2D paradigm and adopt a true 3D design based on triply periodic minimal surface structures, enabling superior performance on gravimetric and volumetric bases. Leveraging the resolution and accuracy of additive manufacturing, we demonstrate a monolithic, gyroidal SOC that eliminates the need for metallic interconnects and sealing components. The monolith achieves optimal spatial utilization, exceptional mass-specific indexes, a straightforward manufacturing procedure and high electrochemical and thermomechanical stability. The specific power and volumetric power density surpass 1 W g⁻¹ and 3 W cm⁻³ in fuel cell mode, and the mass-index and volume-index hydrogen production rates are about 7 × 10⁻⁴ Nm³ h⁻¹ g⁻¹ and 2 × 10⁻³ Nm³ h⁻¹ cm⁻³ in electrolysis mode, nearly an order of magnitude enhancement compared to planar stacks.