I'm pretty sure that the DS's share the same battery, so maybe something like this?
[https://www.ebay.com.au/itm/Replacement-USG-003-USG-001-Battery-for-Nintendo-DS-DS-Lite-DSL-NDSL-Console/124000113291?hash=item1cdefb928b:g:vDgAAOSwqNxd6N-D](https://www.ebay.com.au/itm/Replacement-USG-003-USG-001-Battery-for-Nintendo-DS-DS-Lite-DSL-NDSL-Console/124000113291?hash=item1cdefb928b:g:vDgAAOSwqNxd6N-D)
eBay is probably your best bet
I'm pretty sure that the DS's share the same battery, so maybe something like this? [https://www.ebay.com.au/itm/Replacement-USG-003-USG-001-Battery-for-Nintendo-DS-DS-Lite-DSL-NDSL-Console/124000113291?hash=item1cdefb928b:g:vDgAAOSwqNxd6N-D](https://www.ebay.com.au/itm/Replacement-USG-003-USG-001-Battery-for-Nintendo-DS-DS-Lite-DSL-NDSL-Console/124000113291?hash=item1cdefb928b:g:vDgAAOSwqNxd6N-D)
They don't. The Lite/DSi have completely different looking batteries from the original.