There have been so many new approaches to batteries lately that it's hard to keep track of them all, but most of them have one thing in common: they are all cheaper and safer than lithium-ion batteries.
Listen, lithium-ion batteries are the best we've got on the market right now. They can store a lot of energy in a small, lightweight package -- that's why they're in basically everything we own -- but they also have some drawbacks. The materials needed to make them aren't earth-abundant, which makes them more expensive, especially as you scale up in size. They are a fire risk and they also have a fairly short life span.
For years, researchers have been looking to more abundant, safer materials to create a better battery. Engineers at South Korea's Ulsan National Institute of Science and Technology (UNIST) are just the latest. They have developed a seawater battery that runs on water and salt, which they say could soon rival the lithium-ion battery in performance.
Sodium is the sixth most abundant element on earth, making this battery far cheaper to manufacture and using seawater specifically greatly reduces any chance of fire. The researchers believe that in the future, seawater could be the key to the large-scale energy storage that's needed as the world shifts to more renewable energy. The batteries could also be used as emergency back-up energy for homes, businesses and ships.
The seawater battery works much like a lithium-ion battery as the structure is the same, swapping out lithium for sodium. The university explains:
The battery extracts sodium ions from the seawater when it is charged with electrical energy and stores them within the cathode compartment. Upon electrochemical discharge, sodium is released from the anode and reacts with water and oxygen from the seawater cathode to form sodium hydroxide. This process provide energy to power, for instance, an electric vehicle.
The salt water is not just acting as an electrolyte; according to the American Chemical Society newsletter it is actually a "catholyte — an electrolyte and cathode combined. In batteries, the electrolyte is the component that allows an electrical charge to flow between the cathode and anode. A constant flow of seawater into and out of the battery provides the sodium ions and water responsible for producing a charge."
Currently, the seawater batteries have a lower electrical output than lithium-ion batteries, but the researchers are working on building the batteries in various sizes and shapes to increase the charge rate. They will soon start mass producing the seawater batteries in a testing facility and join cells together in battery packs. The goal is to produce a battery pack by the end of next year that is capable of providing the home energy needs of a family of four.