l298n motor driver draining to much battery

I am building a simple tank that goes forward, after testing my program to make the motors go forward, I noticed that they tend to slow down after a VERY short amount of time. I am using two Dc motors that are running off of an l298n motor driver connected to an Arduino Uno. The motor driver is powered by a 9v battery and the 5v output from the Arduino. Is there anything I can do to fix the motor drive to not drain the 9v battery so quickly? Thanks.

The problem is the 9V battery, they simply are not designed to power motors.
6 AA batteries would be much better.