For a system that old, only third party batteries will be available new -- OEM batteries are generally made for 3-5 years after a system is released, so any you find will be quite old and likely not worth buying.
Hello, I have a Dell Vostro 1014 laptop which is around 11 years old. Laptop works perfectly fine except for its battery. The battery has not been working from quite some time and it works fine on charger plugged in. As this is an old model, I wanted to check if original battery available now? 
Availability of Dell Vostro 1014 battery for replacement