Electrolyte Prevents Cracking in High Capacity Lithium Batteries

Apr, 2021 - By SMI

A team from MIT has created a new electrolyte solution which can handle the chemistry and overcome one of the major bottlenecks in the technology, paving the way for electric vehicles and mobile devices that can last much longer on a single charge.

The concept of a lithium metal battery opens up the possibility of vehicles and mobile devices that can hold much more charge with no additional weight. This is due to the high energy density that a pure lithium metal anode can offer. However, there are some technological problems that must be resolved before it can be sold in the market. Chemical reactions in the electrolyte, which is the solution that transports lithium ions back and forth between the cathode and the anode as it loads, are one of them. More precisely, atoms in metal alloys are susceptible to dissolve in the solution of electrolyte, causing the electrodes to lose mass and ultimately crack and decay as the battery is cycled.

The MIT researchers claim they have discovered a feasible route forward, which resulted from  research that took place earlier in the lithium-air batteries, and another promising alternative that is still years away. Some research team members had created a novel organic-based electrolyte for lithium-air batteries a few years earlier and wanted to see what else they could do about it. The electrolyte was tested with various combination like the typical cathodes used in old lithium batteries that are metal oxides containing nickel, lithium, cobalt, and manganese, as well as a lithium-metal anode. During testing, the new electrolyte proved to be extremely resistant to metal atom dissolution, preventing mass loss and the cracking that normally occurs.

According to the researchers, the new electrolyte could lead to lithium metal batteries that store about 420 watt-hours per kilogram, up from 260 watt-hours per kilogram in today's devices. This could lead to smartphones or electric cars that are the same weight but can be used for much longer periods of time between charges, which could have huge consequences for transportation.