The heat does change it by a chemical and physical method.
It is not possible for any pure solid, as the liquid state is at lower energy then the solid state and you are by definition adding energy. It might be possible for some alloy or mixture of materials, but I am not personally aware of any (but I am by no means a expert on this subject).
There are things similar to what you want, but not exactly. In a typical battery a metal loses a electron and becomes a ion and goes into solution. In this case electricity is not used, but caused by the material going into solution (the ion is now in a liquid solution of some sorts).