High temperature superconducting (HTS) tape can be cut and stacked to generate large magnetic fields at cryogenic temperatures after inducing persistent currents in the superconducting layers. A field of 17.7 T was trapped between two stacks of HTS tape at 8 K with no external mechanical reinforcement. 17.6 T could be sustained when warming the stack up to 14 K. A new type of hybrid stack was used consisting of a 12 mm square insert stack embedded inside a larger 34.4 mm diameter stack made from different tape. The magnetic field generated is the largest for any trapped field magnet reported and 30% greater than previously achieved in a stack of HTS tapes. Such stacks are being considered for superconducting motors as rotor field poles where the cryogenic penalty is justified by the increased power to weight ratio. The sample reported can be considered the strongest permanent magnet ever created.

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Commercially available anode supported solid oxide fuel cells (NiO-8YSZ/8YSZ/LSCF-20 mm in diameter) were anode infiltrated with gadolinium doped ceria (CGO) using a scalable drop-on-demand inkjet printing process. Cells were infiltrated with two different precursor solutions-water based or propionic acid based. The saturation limit of the 0.5 lm thick anode supports sintered at 1400°C was found to be approximately 1wt%. No significant enhancement in power output was recorded at practical voltage levels. Microstructural characterisation was carried out after electrochemical performance testing using high resolution scanning electron microscopy. This work demonstrates that despite the feasibility of achieving CGO nanoparticle infiltration into thick, commercial SOFC anodes with a simple, low-cost and industrially scalable procedure other loss mechanisms were dominant. Infiltration of model symmetric anode cells with the propionic acid based ink demonstrated that significant reductions in polarisation resistance were possible.

The effect of inkjet printing infiltration of Gd 0.1 Ce 0.9 O 2-x in NiO-Gd 0.1 Ce 0.9 O 2-x anodes on the performance of symmetrical and button cells was investigated. The anodes were fabricated by inkjet printing of suspension and sol inks. Symmetrical cells were produced from composite suspension inks on Gd 0.1 Ce 0.9 O 2-x electrolyte. As-prepared scaffolds were infiltrated with Gd 0.1-Ce 0.9 O 2 ink. Increasing the number of infiltration steps led to formation of ''nano-decoration'' on pre-sintered anodes. High resolution SEM analysis was employed for microstructural characterization revealing formation of fine anode sub-structure with nanoparticle size varying in the range of 50-200 nm. EIS tests were conducted on symmetrical cells in 4% hydrogen/argon gas flow. The measurements showed substantial reduction of the activation polarization as a function of the number of infiltrations. The effect was assigned to the extension of the triple phase boundary. The i-V testing of a reference (NiO-8 mol% Y 2 O 3 stabilized ZrO 2 /NiO-Gd 0.1 Ce 0.9 O 2-x /Gd 0.1 Ce 0.9-O 2-x /Gd 0.1 Ce 0.9 O 2-x -La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-d ) cell and an identical cell with infiltrated anode revealed *2.5 times improvement in the maximum output power at 600°C which corresponded with the reduction of the polarization resistance of the symmetrical cells at the same temperature (2.8 times). This study demonstrated the potential of inkjet printing technology as an infiltration tool for cost effective commercial SOFC processing. Graphical abstract

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