Can someone tell me what I need to interface an ADC to a 16 x 2 LCD display? Do I need a microcontroller between it to get it to work?

 

Yes. The display requires a correct sequence of command codes to initialise it, then specific commands and data sent to make characters appear on the display.

So to make the display work will require either a microcontroller, or connection to a PC or some controller that is capable of sending a list of commands and data.