Currently, lithium-ion batteries are the undisputed king of the battery world, but many experts expect magnesium-ion batteries to steal that crown in the near future.
The primary issues with lithium-based batteries are price, efficiency and safety. That is to say, they’re relatively expensive to make, don’t store power all that well and have a tendency to explode. Magnesium, on the other hand, is far more plentiful (making it cheaper) and energy dense than lithium.
To produce power, the Li-ion battery relies on three main components: the positively charged cathode, which is made of metal oxide, the negatively charged anode, which is made of graphite, and the liquid electrolyte—a solvent containing lithium salts—that enables the electric charge to flow between the two poles.
Lithium-ion batteries explode because a manufacturing defect and/or the heat produced during charging causes degradation of the thin wafer separating the anode and the cathode.
When the separator is breached, it causes a short circuit, which can lead to fire or even an explosion!
Magnesium-ion batteries would use a solid electrolyte, hence, no short circuit and explosions.
What sets a Mg-ion battery apart from its Li-ion counterpart is that the electrolyte is solid, not liquid like we find in batteries nowadays. This means that the batteries will be far safer because they will not catch fire like Li-ion batteries are known to.
Another upside of the Mg-ion battery is that its capacity would be double that of a Li-ion battery. For the rest of us, that means smaller, longer lasting electronic devices and electric cars that travel farther on a charge and are safer to drive.