Solid electrolyte batteries have been heralded as a major breakthrough for electric cars for years, but they have yet to reach mass adoption in vehicles that customers can actually buy. New research from MIT and the Technical University of Munich explains one of the reasons why their development is so slow.
The main problem is dendrites, the tiny metal spikes of lithium that can grow inside the battery. When they spread through the cell, they can cause short-circuiting and damage, which is one of the biggest obstacles to reliable operation of solid-state batteries.
In these batteries, the liquid electrolyte is replaced by a solid material, which enables the movement of ions between the anode and the cathode. In theory, such a design can bring greater range, faster charging and less risk of fire compared to traditional lithium-ion batteries.
Solid state batteries are plagued by lithium dendrites inside the cell
Researchers have now turned their attention to the structure of the solid electrolyte itself. It consists of a large number of microscopic grains, each of which is separated by a grain boundary. According to the new paper, precisely these borders have a hidden electrical imbalance.
This imbalance hinders the movement of lithium ions through the battery and allows electrons to accumulate at the grain boundaries. Such conditions encourage the formation of dendrites, which can then penetrate the electrolyte and cause failure.
The team studied a solid electrolyte called lithium lanthanum zirconate. With the help of AI tools and specialized methods, they mapped how electricity passes across grain boundaries and where problems arise.
Once they understood the cause of the imbalance, they changed the way the electrolyte was treated to reduce damage and allow the lithium ions to move more freely. This reduces the possibility of dendrite formation, but also the loss of energy in the cell.
The result was significant. The researchers report that the energy density was 300 percent higher than the baseline sample. This means that such a battery can be charged and discharged faster than classic solid solutions, with a potentially longer service life.
However, this is a laboratory experiment, not a finished battery ready for cars. Manufacturers still have to work out price, mass production and defect-free quality control. Nevertheless, this research provides an important clue. If the problem of grain boundaries can really be controlled, solid electrolyte batteries could be approaching the moment when they are no longer just a promise, but a practical technology for electric vehicles, reports MSN.