compound verbs - 気力がつきかけていた: What meaning does かける have here? And which つき is this?

頭のどこかで諦めてしまっている。体に力が入らず、何より気力がつきかけていた。

I'm not sure how to interpret the meaning of かける in this sentence. What meaning does it have here?

Also, is this つき 尽き or 付き?

Answer

It's 尽き

かける means almost

Example:

終わりかけた

(I) almost finished