Sodium-ion batteries are a type of rechargeable battery that use sodium ions as the charge carriers. They operate similarly to lithium-ion batteries but utilize sodium, which is more abundant and less expensive than lithium. This makes sodium-ion technology an attractive option for large-scale energy storage and electric vehicles. These batteries consist of an anode, a cathode, and an electrolyte, allowing sodium ions to move between the two electrodes during charging and discharging. Research is ongoing to improve their energy density and cycle life, making them a promising alternative for sustainable energy solutions in the future.