De or het cadmiumbatterij?

The correct Dutch article is:

de cadmiumbatterij

Rule Words ending in -ij and -erij: usually de. See the rule

How to use cadmiumbatterij

the cadmiumbatterijde cadmiumbatterij
this cadmiumbatterijdeze cadmiumbatterij
that cadmiumbatterijdie cadmiumbatterij
our cadmiumbatterijonze cadmiumbatterij
your cadmiumbatterijjouw cadmiumbatterij
every cadmiumbatterijelke cadmiumbatterij
which cadmiumbatterij?welke cadmiumbatterij?
a big cadmiumbatterij / the big cadmiumbatterijeen grote cadmiumbatterij, de grote cadmiumbatterij

Dutch words ending in cadmiumbatterij

nikkel-cadmiumbatterij

In compound words, the last part decides the article. See the rule