Lithium-ion batteries will continue to be the current standard for electric vehicles for a while longer according to Industry Week. That’s despite the fact their limited storage capacity causes users range anxiety, and their chemistry can become unstable. Researchers are exploring silicon-graphite composites as a workaround. However, they are still struggling to overcome silicon’s expansion rate.
Lithium-Ion Batteries & Silicon-Graphite Composites
Lithium-ion batteries popularly use graphite as negative anode electrode, while they layer a lithium compound in the positive one. However, the carrying capacity of the graphite restricts the volume of storage, and hence the charge life of the device. This in turn encourages faster charging causing more rapid degradation of the materials.
To counter this, battery manufactures have begun using silicon based materials because silicon is abundant and conducts electricity well. Moreover, they can store electrical charge with only modest expansion occurring. A pure silicon anode (instead of graphite) would take this mega step further but we need to manage the expansion factor first.
Solving the Problem at Experimental Level
But, We Will Have to Use Composite Solutions in Practice
The physical limitations of pure silicon mean we are stuck with silicon-graphite composites for a while longer. However, battery manufacturers know how to add small amounts of the material to achieve capacity step changes. Their recipes are closely-held trade secrets, although the factor is generally around 10%.
This is the only proven way to significantly increase lithium-ion battery performance, industry experts say. However, if they add too much silicon then this cracks and crumbles away from the graphite. Therefore, Industry Week believes the new decade will see battery makers gradually increase the ratio instead, as they move in the direction of pure lithium-silicon batteries.
Silicon-graphite composites will make a valuable contribution to the green economy. But solid-state technology will become an even more dominant game-changer in the second half of the decade. That will be the day we hope to put range anxiety and lithium-flammability finally to bed.
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