Lithium-ion batteries store significantly more energy per unit weight and volume compared to other rechargeable batteries like nickel-cadmium or lead-acid. Li-ion batteries typically have a longer lifespan than other rechargeable batteries, withstanding hundreds of recharge cycles before significant degradation. They exhibit minimal self-discharge, meaning they lose less charge when stored compared to other battery types. Their high energy density allows for lightweight and compact battery designs, ideal for portable devices.