Author:
Ally Winning, European Editor, PSD
Date
03/15/2023
PDF
The new battery uses a dense, porous, ceramic scaffold as a separator between the anode and cathode
Solid-state batteries offer the industry many opportunities. They are inherently safer than the batteries that we use today for consumer devices, electric vehicles and other types of energy storage. This is because, as their name suggests, they use a solid electrolyte instead of a liquid one. That means that they are not prone to spontaneous combustion, and they don’t need a thick metal casing to both contain the effects of combustion, and to stop the caustic electrolyte leaking. The lack of a casing also means the cells tend to be smaller, packing more energy into the same space. They can also be charged faster.
However, they do have a few problems that has so far stopped the technology becoming mainstream. The biggest of those is that they tend to expand and contract, which can cause cracks in the electrolyte, shortening the useable lifetime of the battery, or causing their outright failure. This is because solid state batteries usually use a planar structure, meaning that the electrolyte is a solid block that is sandwiched between the anode and cathode. When the battery charges and discharges then the anode expands and contracts, which can crack the electrolyte, or separate it from the anode. To try stop this phenomenon usually requires a way to apply pressure to the battery to keep it together, which usually means increasing the volume. Some solid state batteries also require heating to get optimal performance. Another problem that solid state batteries must overcome before being commercially viable is the formation of lithium metal dendrites. Dendrites are metallic formations on the anode that can grow to the cathode and cause short circuits.
University of Maryland spin-out company, Ion Storage Systems has created a 3D ceramic electrolyte architecture that prevents the formation of dendrites and does not expand, and therefore need compression or require heating. The new battery uses a dense, porous, ceramic scaffold as a separator between the anode and cathode. The porous scaffold acts as an electrolyte, which also stops dendrites forming and the battery self discharging. The lithium metal anode is infiltrated in a porous ceramic framework above the dense layer, creating uniform pathways for Li+ and electrons that lead to a lower resistance and higher energy density. The architecture also seals the anode, making it compatible with a wide range of existing and next-generation cathode chemistries.
The technology is further along the road to commercialisation than many other solid state designs. Ion has already been funded by the Defense Logistics Agency (DLA), the Department of Energy’s (DOE) Advanced Research Project Agency–Energy (ARPA-E), DOE’s Office of Energy Efficiency and Renewable Energy (EERE), and the Army Research Lab (ARL). As the funding suggest, the battery is of particular significance for military use, at least initially. Ion’s first customers will be the US army, who will use the batteries to power military wearables. The company is now expanding its 20,000 square foot facility, which is located in Maryland’s Prince George's County and getting ready for pilot production to deliver alpha samples. Then the company intends to scale up to commercial production.
