High-temperature superconductors and their large-scale applications

Abstract

For decades, superconductor materials have promised high power, high efficiency and compact machines. However, as of 2024, commercial applications are limited. One of the few successful examples is represented by low-temperature superconductor (LTS) materials that are used for magnetic resonance imaging (MRI) in hospitals worldwide. High-temperature superconductors (HTSs) can support currents and magnetic fields at least an order of magnitude higher than those available from LTSs and non-superconducting conventional materials, such as copper. However, HTSs are seldom used, even if there are important areas where these materials could perform better than conventional ones or LTSs. For example, HTSs can replace conventional materials in wind turbines and aeroplane motor engines to improve power-to-weight ratios. In tokamak fusion reactors, HTSs might enable sustainable positive power outputs. Additionally, in medicine, HTSs might replace LTSs for smaller MRI machines, producing high-resolution images, without the need to use a scarce resource such as helium (fundamental for LTSs). The primary barriers to deployment are alternating current loss, quench, heat losses and costs. Developments in HTS manufacture have the potential to overcome these barriers. In this Review, we set out the problems, describe the potential of the technology and offer (some) solutions. High-temperature superconductors are now used mostly in large-scale applications, such as magnets and scientific apparatus. Overcoming barriers such as alternating current losses, or high manufacturing costs, will enable many more applications such as motors, generators and fusion reactors.