When I first got my 5D IV, I used the same Canon LP-E6 battery from my older EOS 6D and then later added on a second LP-E6N.
These days you can also get LP-E6NH which have around 15% better life over the LP-E6N.
The nice thing about the Canon batteries is you get this "forwards and backwards" compatibility,
In terms of brands, I only use Canon. And then I only purchase from reputable (and authorized Canon) dealers such as B&H Photo.
I would definitely avoid eBay, Amazon and other sellers such as Walmart where there's no guarantee as to if the battery won't be counterfeit.
--
Ricky
Camera: EOS 5D IV, EF 50mm f/1.2L, EF 135mm f/2L
Lighting: Profoto Lights & Modifiers
