Hm. This is nitpicky, but I'm curious as to why you would think psy energy functions like a liquid when given physical form. Why not a gas? Indeed, a gas would make more sense, since spirits are described as "dissipating" when defeated. Gases are the only substances that can dissipate, really.
In fact any fluid (liquids and gases are fluids) can be dispersed in some other fluid (but not necessarily into any fluid). If the amount of one fluid is significantly smaller than the other it appears that the first fluid disappears into the other.
In that sense, the psy energy would be spread all over the place and the people (humans or not) that have psy skills can transform the psy energy to other typels of energy (producing heat or movement) and transform other types of energy into psy energy (creating cold regions or absorbing kinetic energy reducing the impact created).
Regarding spirits, if they can control the psy energy, they may choose to create solid areas in a shape of a weapon. The edge of the weapons being like ice seems reasonable, due to some spirits using cold attacks.
Under this view, some of the spirits may be more like a dense liquid, thus more susceptible to physical attacks and other spirits may be more like a less dense liquid or even a gas, thus less susceptible to physical attacks.