Is it permissible for a divorced woman to seek divorce and waive the deferred mahr, or to seek khul' from a husband to whom she feels no psychological comfort?

Live with your husband honorably, look at his good qualities, and discuss with him what you dislike. Do not hasten to seek divorce unless all means of reconciliation have failed. If you are unable to fulfill his rights due to overwhelming hatred for him, then you may seek khul' (divorce at the wife's instance) from him for compensation, as Allah Almighty says: "But if you fear that they will not keep within the limits [set by] Allah, then there is no blame upon either of them concerning that by which she ransoms herself." [Quran 2:229] And if he divorces you without compensation, there is no sin.