Is a wife who seeks a divorce (khul') from her husband, after being subjected to physical and verbal abuse and his refusal to reconcile, considered sinful?

There is no sin upon a woman for divorcing her husband who mistreated her, to the point that she hated him, due to the words of Allah Almighty: "But if you fear that they will not uphold the limits of Allah, then there is no blame upon either of them concerning that by which she ransoms herself." Khul' (divorce at the wife's instance) is permissible due to mistreatment between the spouses. Separation is the best option in this case, unless the husband repents, regrets, and improves his character.