Is it true what is narrated about a female Companion who wanted to donate her hair in one of the battles of jihad due to her poverty? And if it is true, what is the name of this female Companion and what are the details of the incident?

We have not come across a story in the biographies and historical accounts of a female Companion (Sahabiyyah) who donated strands of her hair for jihad. This is religiously objectionable (munkar), and a woman's hair is part of a dignified human being. It is not permissible for a non-mahram man to look at it or touch it, whether it is attached or detached, according to the jurists of the Hanafi and Shafi'i schools. Some jurists have explicitly stated the impermissibility of using detached hair due to the dignity of the human being.

The story of the woman who donated her hair for jihad in the way of Allah pertains to a woman from Raqqa during the era of Harun al-Rashid, and she was not a Sahabiyyah. This account is more acceptable than others because it was narrated with an acceptable historical chain of transmission. That woman is hoped to receive reward for her good intention, but this does not mean her action is permissible from a religious perspective.