I've personally used this one in my quarantine tank. Works great. Kicks on when the powers lost. And you can set it to either run constantly or pulse, and you can extend the pulse increments.
USB Battery Powered DC Air Pump - Single Output
Single Output | Battery Powered | Silent Cobalt USB Powered air pumps use a 5V DC powered motor that also has an onboard battery that can last up to 24 hours without a direct connection to a power supply. It can run continuously or with a 10-second on/off cycle in the battery powered mode to...www.bulkreefsupply.com
I have one of these as well. I used the D battery powered pumps for years, but got tired of remembering to change batteries, have batteries go bad, etc. I plan to add more of these in the future.