Can the iPod Touch battery be replaced?

I use my iPod Touch mainly for listening to podcasts. I'm getting barely 45 minutes on a fully-charged device with wired earbuds. Besides the podcast program, my VPN is running. Wifi and Bluetooth are both activated. Are any of those three (VPN, wifi, Bluetooth) notorious battery hogs? Can I have the battery replaced or is a new iPod my only choice? Is there a better device for listening to podcasts? I think it's a Version 6; the model number is NKH2LL/A.