Absolutely and it is also safe to do so. Basically you are using the laptop as a desktop. This web page at Tech 21 Century has more detail. I have a Latitude E5430 and the battery has long ago lived out it's life. I use the laptop with only the adapter and it runs fine. Keep in mind though that you must first shut down the system properly if you plan to disconnect it from power. Once you disconnect power it will shut off immediately not saving any of your work. Also disconnecting in that manner can cause corruption of Windows files.
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DS 07/20: Is it ok to use a laptop without the battery?