What are the worst batteries called?

The worst batteries are often referred to as "alkaline batteries" in terms of performance for specific applications, particularly when compared to rechargeable options like lithium-ion or nickel-metal hydride batteries. They are less efficient in high-drain devices and can leak over time. In a broader sense, poorly designed or low-quality batteries, such as some generic or counterfeit brands, can also be considered among the worst due to their tendency to fail, leak, or provide inconsistent power.