Speeding up complex data write.table

I have a large number of data.frames and I want to record them (in different places). At the moment I am using write.table()

but it will take me about 2.5 days to get all of them out.

I tried a function fwrite()

from the library data.table

, however, it is not implemented for writing complex numbers.

Do you have any suggestions on how to speed up the discharge process?