Sodium-ion batteries is an area of research within materials science, chemistry, and engineering focused on developing electrochemical energy storage devices that utilize sodium ions as charge carriers. This field investigates electrode materials, electrolytes, cell architectures, and fundamental ion transport and reaction mechanisms to achieve reversible energy storage cycles, aiming to provide a cost-effective and sustainable alternative to lithium-ion technology by leveraging the abundance of sodium resources for applications such as grid energy storage and electric vehicles.