Recently the DC cable from my AC/DC adapter to my laptop broke. I removed the broken section and it works again. Now the cable is too short for my taste and I would like to replace it. I heard from an electrician, that you should stick with the coaxial cable type (as it was used for the device, see picture below), saying something about the higher frequencies involved due to the switching-mode transformer. This is supported by the fact, that all major laptop producer seem to choose this kind of cabling.
So firstly I was wondering if that is true. After all, the output should be DC. Even if it contains spurious HF components, what would the coaxial cable help about it? Would using a "regular parallel cable" and a ferrite choke ring have the same effect?
Secondly I could not find any cable like this anywhere for sale¹. Do they have a special name under which they are sold?
¹ I was searching for "DC coaxial cable", "Laptop power coaxial cable", etc on DigiKey, ELV, eBay, Aliexpress, Reichelt and Conrad and found only either non-coaxial cables or RF-coaxial cables, but no high-current (4A) flexible DC coaxial cables.