No, you don't want to try that as typically all residual hearing is lost in the implanted ear. In some cases where it is not, the hearing isn't quite as it was prior to the implant anyway.
So, the thought might occur for one to have a CI on the worst ear to preserve the good ear. The problem with that concept is one may not be successful compared to having a CI in the good ear.
Basically, one picks their poison...a successful outcome at the expense of residual hearing or a not so successful outcome but still have the good ear left. Personnally when one comes down to the nitty gritty...I much perfer a successful outcome over anything else and the rest is irrelevant. I would never embarked on a CI if I didn't intend to make it work. Otherwise, what is the point?