I recently dug out my old Creative Zen Vision W but being circa 2006, the battery was roached. You can’t get replacements anymore but since the battery is removable, I found some cheap pouch cells that were the right thickness and soldered them to the existing connector/charge control board.

The original was 1650mah iirc, the new ones are allegedly 2500. From some basic testing, I believe its more than it used to have. $15 all in, considering no one makes these anymore and NOS ones go for $190, I’m happy to have 2 functional ones again.