where can i buy an removebole battery for an macbook from

The device is 16 years old, obsolete and no longer supported.

The cost to replace the battery, and Apple will likely not do the work because of non support, will very likely exceed the worth of the unit.

Your money will be better spent on a new, or newer, computer.

Perhaps should you search the few quality third party web site sources online

to see what they have to offer at this time; prior years, those vendors had some.

Identify your MacBook model - Apple Support

Helps to find About your Mac, if the unit runs so the unit build model year

is a known factor. There are several different MacBook series & vintages.

One whose had very good reviews, and products of most types for Apple

including update, upgrade, & replacements; macsales OWC is US-based.

If you use MacTracker (free database for most Apple products) that can

tell you a lot more than most users need; including how to use information

to order correct replacement or upgrade parts. Specific part numbers.

Occasionally I look through their pages, on a whim; and sometimes order.

I've ordered and received batteries, original Apple MagSafe power adapters

and memory chip upgrades; plus upgrade HDD/SSD replacement drives.

For all variety of hardware upgrade availability see OWC main webpage & 800#

To see what they have for specific build-model products, check here to locate:

https://eshop.macsales.com/upgrades/ (Notebooks: macbook-pro/macbook-air)

They will 'ship' batteries; there are limits due to safety standards. Usually

through parcel services; and federal restrictions, like any other source has.

https://eshop.macsales.com/shop/Apple/Laptop/Batteries

https://eshop.macsales.com/shop/specials

Due to limited local inventories where I am, these may (or not) be what I would

get. Shipping & 'extra charges' for items to Alaska, can break most good deals.

..Away from the only roads here, most AK towns require flight service to access.

My opinion is you'd be wasting your money. If the battery is dead, a new cable is not going to fix that.

If the battery is removable, I have no idea, you may find one on sites such as eBay. Caveat emptor applies

I get the feeling you're beating a dead horse here. At 16 years old it's time to replace it.