What's the difference? Is a volitional sentence simply a weaker form of an imperative sentence?
I wasn't aware that we had them in English. My wife uses them quite a lot, but that's because she speaks Mandarin.
Given that this is something from Chinese or Japanese, which is being applied to English (either by you or something you have read/heard), please give a precise definition of what you mean.
[Edit: Why on Earth was that down-voted? Does someone believe that English has volitional sentences? It is for the OP to clarify the meaning of the (Asian-language) term, so that people can respond to it in relation to things with similar aspects in English.]