Welcome to iMore! If your device will at least power up, there are a couple of things you can try:
1. Reset it by holding the power button and home button down until you see the Apple boot logo. Try charging again.
2. If that doesn't work, perform restore, preferably using iTunes and setting the phone up as a new device.
3. If you're still having issues, contact Apple Support
If your iPhone won't even turn on, then there's obviously a hardware problem with the phone itself. Keep in mind batteries don't last forever. That lithium ion battery is designed to retain 80% capacity for 500 full battery cycles (fully draining, then fully charging). If it's a few years old it could just be that the battery has exceeded its operating life.
When you said "different chargers" you meant different lightning cables AND wall chargers, correct?