Li-ion, or lithium-ion, is a type of rechargeable battery commonly used in portable electronics, electric vehicles, and renewable energy storage. These batteries are favored for their high energy density, which allows them to store more energy in a smaller size compared to other battery types. They operate by moving lithium ions between the positive and negative electrodes during charging and discharging. The main components of a Li-ion battery include the anode, cathode, electrolyte, and separator. The anode is typically made of graphite, while the cathode often consists of lithium metal oxides. Li-ion batteries are known for their long cycle life and low self-discharge rate, making them efficient for everyday use in devices like smartphones and laptops.