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High temperature superconductors (HTS) and solid oxide fuel cells (SOFCs) both offer the possibility for dramatic improvements in efficiency in power applications such as generation, transmission and use of electrical energy. However, production costs and energy losses prohibit widespread adoption of these technologies. This thesis investigates low-cost methods to tailor the structures of HTS wires and SOFCs to reduce these energy losses. Section I focusses on methods to produce filamentary HTS coated conductors that show reduced AC losses. This includes spark-discharge striation to pattern existing HTS tapes and inkjet printing of different filamentary architectures. The printed structures are directly deposited filaments and ‘inverse’ printed tracks where an initially deposited barrier material separates superconducting regions. Furthermore, the concept and first stages of a more complex ‘Rutherford’ cable architecture are presented. Additionally, Section I investigates how waste material produced during the manufacture of an alternative low-AC loss cable design, the Roebel cable, can be used to make trapped field magnets that produce a uniform magnetic field profile over a large area. This trapped field magnet work is extended to study self-supporting soldered stacks of HTS tape that demonstrate unprecedented magnetic field uniformity. Section II looks at how nanostructuring porous SOFC electrodes via solution infiltration of precursors can improve long-term stability and low temperature performance. Inkjet printing is utilised as a scalable, low-cost technique to infiltrate lab-scale and commercial samples. Anode infiltration via inkjet printing is demonstrated and methods to increase nanoparticle loading beyond ~1 wt% are presented. Symmetric cells with infiltrated cathodes are shown to have improved performance and stability during high temperature aging. Additionally, the sequence of solution infiltration is found to be important for samples dual-infiltrated with two different nanoparticle precursors.

A next generation high field accelerator magnet (>15 T @ 4.2 K) has yet to be achieved. The superconducting accelerator magnet has three major parts; the superconducting composite winding, the wrapped insulation, and the impregnation. The conductor/wrap/impregnation (CWI) composite has a multitude of material and interfacial properties that determine the magnet’s “stability” and “protectability”. These two metrics are important to the successful operation of a superconducting accelerator magnet. The superconducting state within an accelerator magnet is exposed to a multitude of instability mechanisms which can lead to a local superconductive to normal state transition. This “normal zone” can recover to the superconducting state or can grow catastrophically in the form of a quench. Stability, the ability of the CWI composite to avert a quench, is determined by minimum quench power (MQP) and minimum quench energy (MQE). Protectability, the ability of a magnet constructed out of a CWI composites to mitigate a quench, is determined by the maximum voltages, temperatures, and mechanical stresses generated during a quench and the ability of the CWI composite to handle that exposure.In this document, material properties related to stability and protectability are discussed for CWI composites composed of Nb3Sn or Rare Earth Barium Copper Oxide (REBCO) superconductors. This work discusses composite structure and processing in the context of CWI composite stability and protectability. Analytical models will be used to generate quick solutions and expectations that accompany changes in the CWI composite. Single strand superconducting composites, superconducting cable composites, and entire CWI composites have been measured under current excitation by various sources, including a 30 kA superconducting transformer. Two special materials selections: (i) a high thermal conductivity impregnant and (ii) a metal to insulator transitioning insert for interconductor contacts, have been integrated into a CWI composite and their properties measured. It was shown that MQP is the property of concern for REBCO composites and that structure and processing, a strong determining factor for stability, stability and protectability, can simultaneously be enhanced (i) by the use of a new high thermal conductivity impregnation, and (ii) nanoparticle consolidations which can function as metal to insulator transitioning inserts for REBCO coated conductor interfaces.