Hi, most accepted Dark Energy theory is not based on material/dark particles pushing objects away from each other, you may mix it with Dark Matter theory (explaining "missing" mass of galaxies etc). However, I see that this thread was to explain the issue that universe is larger than light speed would allow, and for this purpose explaining the topic on the currently accepted hypothesis/theories is logical to keep the answers simple. Discussing proving of the dark energy theory and especially doscussiong alternative theories for sure deserve their own thread.

There is new empty space emerging from nothingness, and this is different thing that two objects travelling from each other. Think it like this: you and I are located still 1 lightyear from each other, and suddenly 10 light-years worth of new space emerges between us. It would endeed SEEM to us that we would have broken law of relativity, but actually we have not moved faster than light (or in this case, ww havent moved at all!) - there just have becomw more empty space between us. (Edit: accidentally posted too early)

Long story short i) >>c expansion (hyperinflation) at the beginning of universe and ii) space between matter in the universe is expanding constantly that causes faster-than-light expansion (new-born empty space also expanses so the expansion is exponential and not limited by the speed of light). So again, new emerging space between the objects or the universe cause the universe to expand faster than light, although all objects in that space are not able to move faster than light in relation to each other.