For "normal" DC-DC converters it's the losses in the semiconductor switches and diodes that dominate[1], unless cheap inductors or capacitors are used. High-ef

For "normal" DC-DC converters it's the losses in the semiconductor switches and diodes that dominate[1], unless cheap inductors or capacitors are used. High-efficiency DC-DC converters often use a resonant tank circuit[1], which supports high-frequency operation and zero-current or zero-volt switching, which together significantly reduces switching losses. In such a circuit I imagine superconducting inductors/transformers and superconducting capacitors could be beneficial to improving efficiency further. Keep in mind though that resonant DC-DC converters can reach 98% (or higher) efficiency already[3] with current tech. [1]: https://www.analog.com/en/technical-articles/an-efficiency-primer-for-switchmode-dcdc-converter-power-supplies.html https://www.analog.com/en/technical-articles/an-efficiency-p... [2]: https://www.monolithicpower.com/understanding-llc-operation-part-i-power-switches-and-resonant-tank https://www.monolithicpower.com/understanding-llc-operation-... [3]: https://ietresearch.onlinelibrary.wiley.com/doi/10.1049/iet-est.2019.0092 https://ietresearch.onlinelibrary.wiley.com/doi/10.1049/iet-... (random example)