Photo by Denny Müller on Unsplash

Just like humans need electrolytes in our bodies, electrolytes are critical to the battery’s power, lifetime, speed of charging and cost. We can go to Gatorade for an electrolyte boost, but what is done with electrolytes for battery manufacture? That’s what I discussed in the latest Barry on Batteries in Chemical Processing; here’s an abbreviated version.

There’s a growing market for battery chemicals, both organic liquid electrolytes and solid-state electrolytes (SSEs). Yet before we continue, we must agree that there are no universal electrolytes.

Typical electrolytes use lithium hexafluorophosphate (LiPF6) salts as they remain the only candidate to be used due to their well-balanced properties, such as high ionic conductivity, good electrochemical stability, and excellent wettability of the electrodes. With the salts, solvents are used such as ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) as well as a small number of additives (which are unique to each company).

Comparing electrolytes for battery manufacture

Each main type of electrolyte has its own advantages and drawbacks. Liquid electrolytes suffer from potential safety issues such as high flammability, poor thermal stability, and liquid leakage. During cell manufacturing, for example, each cell must be filled with the electrolyte, sealed, pressure tested, and packaged.  To address these safety concerns and many operational steps, alternatives are being developed using SSEs.

Generally, the SSE can be classified into solid polymer electrolytes (SPEs), inorganic solid electrolytes (ISEs), and composite solid electrolytes (CSEs). SSEs are still being investigated. Still, they have demonstrated numerous advantages over the organic liquid electrolyte. These include:

  • Non-flammable
  • High-temperature stability
  • Non-volatilization eliminates risk of combustion or explosion (seen with organic liquid electrolytes)

Innovation in electrolytes continues

Every day, there are new alternatives for EV batteries. I just heard about a rubber-based organic polymer that works well for lithium-ion transport and improved mechanical stability. At a recent conference, there was a presentation about solid or quasi-solid electrolytes with high performance at ambient temperatures to address safety concerns. I also attended a session on a liquefied-gas electrolyte. Research and development along with experience will keep the chemical industry in the forefront of electrolyte technology.

Chemical process engineering is well positioned for growth with our skills and experience in multiple, flexible process operations. Let’s discuss innovative approaches and continue the development together.