For example, [Berry Berry Sneaky] has recently put together a step-by-step guide on swapping the common ThinkPad rectangular charging port (also used on ThinkBooks and other Lenovo machines ...
With laptop chargers and portable battery packs using ... [victorc] was trying to do just that, purchasing an adapter cable to charge a ThinkPad. Things didn’t quite work out of the box, so ...
Still, for those who are fans of the ThinkPad X Series but are especially budget-constrained, Lenovo's ThinkPad X280 is a solid alternative. Just make sure you don't forget your charger.