That's somewhat debatable, if you mean 'expansionist' like Russia would like to rebuild the USSR or a new Russian Empire.
What Russia is trying to do is ensure it has a strategic buffer zone between it and the West and friendly rulers and states on its borders, much like any state with Russia's military history would be interested in doing. Combined Russian/Soviet casualties in WW1 and WW2 were on the order of ~60mm people out ~160mm total.
Both NATO and the EU have progressively expanded towards the former Soviet bloc since the fall of the USSR. From the West's perspective, this is bringing liberal multiparty democracy and stability to an unstable Eastern Europe. But from Russia's perspective, why should it fully trust the West that was so recently its enemy, and when the attempted adoption of liberal democracy and capitalism in the 90s failed so spectacularly (Russia's GDP fell by a full 50% and life expectancy dropped by years [2]).
Not trying to shill or defend Russia's invasion of Crimea or Ukraine here, but if you just look at the map of a formerly hostile alliance moving steadily eastward and you were Russia, would you really just throw up your hands and say 'yes, that is how the world should be' and tacitly accept it? [1]
[1] https://en.wikipedia.org/wiki/Enlargement_of_NATO#Vilnius_Gr...