Researchers at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have developed a new electrolyte mixture to overcome the challenges of lithium-ion battery (LIB) performance.
For decades, scientists have been searching for new electrode materials and electrolytes that could provide high power densities, greater capacity densities and better safety. The versatility of lithium-ion battery means it can be tailored to powering cell phones, laptops, power tools and electric vehicles. However, the growing demand for electric vehicles have led scientists on a vigorous hunt for new electrode material to increase the performance of LIBs.
Typically, silicon anode is the popular replacement to the current graphite anode; its large energy storage capacity, low price and its abundance are attractive advantages. However, a silicon-based anode in a lithium-ion cell becomes very reactive, degrading the cell overtime and consequently affecting the length of its life cycle.
To overcome this challenge, Argonne scientists have developed a unique electrolyte additive strategy, adding a small amount of a second salt containing charged metal cations, giving silicon anodes an increased surface and bulk stabilities. This mixture, known as MESA (mixed-salt electrolytes for silicon anodes) improves the cycling life.
Baris Key, a chemist in the Chemical Science and Engineering division at Argonne, believes this ‘new chemistry is simple, scalable and fully compatible with existing battery technology.’
The MESA-containing electrolytes work during charging when the metal cation additions in electrolyte solution migrate into the silicon anode, along with lithium ions. This forms lithium-metal-silicon phases which are stable and much larger in energy density than the cells with graphite.
Key believes that if this intervention becomes part of the production process of silicon anodes, it will have a far-reaching impact.
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