This document describes a new type of battery that is safer and longer lasting than current lithium-ion batteries. It works by using sodium ions rather than lithium ions and two different solid materials for the anode and cathode. Sodium ions can move back and forth between these solid materials during charging and discharging. This new battery design avoids using flammable liquid electrolytes and is less likely to catch fire. It also has the potential for higher energy storage capacity compared to existing rechargeable battery technologies.