Partially filled metal containers work well for long term emergency storage where it could stay frozen for months on end. Metal containers make it easier to melt a big block of ice rather than trying to chip it out of a plastic bottle.

For shorter term storage you can try wrapping your water bottle with some kind of insulation and store it upside down so that the ice forms in the bottom first and does not block the drinking spout. Also add a bit of gator aid or other mix which will lower the freezing point of the water.