Batteries power our lives: we rely on them to keep our cell phones and laptops buzzing and our hybrid and electric cars on the road. But ever-increasing adoption of the most commonly used lithium-ion batteries may actually lead to increased cost and potential shortages of lithium—which is why sodium-ion batteries are being researched intensely as a possible replacement. They perform well, and sodium, an alkali metal closely related to lithium, is cheap and abundant.