Qi is really just Qi. But at times it is useful in speaking about Qi, in the context of things like Qi Gong, cultivation practice, esoteric studies or traditional healing to describe particular interactions of Qi with our body or our consciousness through the use of metaphorical conditions. However, this has led over the years to different systems or teachings in esoteric schools to end up using a variety of terms, like "positive qi", "negative qi", "Yin Qi" or "Yang Qi", "Natal Qi", "Active Qi" or "Stale Qi"; but all of these gradually came to be thought of as different "types" of Qi, which is inaccurate.
As an example, let's consider the example of "stale Qi":
There are two ways to understand Qi in any way that Qi could be said to be 'stale'. The term is a deceptive because it implies that it is the Qi that is bad or corrupted or in some sense different from normal Qi.
The first is in the sense of physical well-being, where if someone has failed to be natural for a long time, developing harmful physical habits that lead to physical tension, a failure to breathe naturally, tightness/restriction of the body in varied ways, then the circulation of Qi through the body is not open and fluid, and so Qi will tend to accumulate only in certain areas of the body and not others, leading to physical disharmony. Notice that it is not in fact a problem with Qi, or that Qi is any different, it is a problem with the body and its ability to be open and receptive and fluid in relation to Qi.
The second is in the sense of understanding Qi not only as life-force but as Will. Our will is directed to certain things. We put our will into certain things. This includes things that must be done in the immediate sense, like very ordinary things, and also things that we are trying to achieve in a bigger sense, but it also means anything we've intentionally or unintentionally invested ourselves in. This investment means that some of our will, our Qi, will be directed in certain ways, and normally this isn't a problem, it's perfectly normal. But if we have invested our will into things that we cannot resolve, into things that are unreal, or things that are no longer real, our attention and our emotions (fear or desire) and our mind and our pain clinging to those things in spite of their unreality, then the Qi gets locked in to being invested in that. Part of our will is stuck there.
That manifests also in the body, as tension (tension here meaning anything from physical rigidity to posture, to breathing, to other symptoms like sleeplessness or intestinal troubles, to serious disease). The Qi there is 'stale' because it is stuck clinging to something unresolved and that cannot ever be resolved in the usual way. Once again note that the problem is not with Qi, or that the Qi is different, but rather a problem that our mind is locking-in our Qi, limiting its fluidity because of our obsessions.
So the ways to resolve these sorts of problem are either by physical practice (Qi breathing) or by Virtue (through self-inquiry). The former uses the body to loosen the bonds of the mind, the latter uses awareness to loosen these bonds. Typically, a combination of both is best.