The verb entspannen
is most commonly used transitive, i.e. with an accusative object. Therefore, while English relax
is often used without an object, this meaning is preferrably expressed in German with a reflexive pronoun:
Zeit, mich zu entspannen
Moreover, it is very uncommon to negate haben
(the full verb) with an amount, a mass noun, or similar contexts. In German, you have no / none of something. You only don't have a specific item:
Ich habe keine Zeit gehabt.
You end up with:
Ich habe keine Zeit gehabt, mich zu entspannen.
You could also say:
Ich habe keine Zeit mich zu entspannen gehabt.
But this word order makes the sentence a little "bumpy".
Alternatively, you can nominalize entspannen
. I suppose this is the most common phrasing:
Ich habe keine Zeit zum Entspannen gehabt.
Also note that Zeit
, being a noun, has to be capitalized regardless of its position in the sentence.