For replaceable rechargeable batteries (for a regulated and/or mechanical "mod"), you want safe chemistry, high drain batteries called
IMR ( Li-Mn chemistry). Li-ion or ICR chemistry batteries (generally called "protected" batteries) are no longer used in vaping. Never use over-the-counter Alkaline batteries from hardware/electronic/department stores.
AW, Orbtronic, Panasonic, Samsung, and Sony are reliable brand name IMR manufacturers. Ego batteries are Li-Po chemistry.
Battery Basics for Mods: IMR or Protected ICR?
Where you buy your batteries can be just as important as which ones. Many unscrupulous manufacturers and vendors selling batteries these days. Buy only from reputable, trusted vendors such as RTD Vapor, Lighthound, Illumination Supply, or Orbtronics.