We are sharing a large article by Nature.com, while breaking it up into smaller chunks. The overall topic is the future of lithium-ion technology. Or perhaps it is the lack of it, because cobalt is scarce. Nature.com argues it is time to start replacing lithium batteries, especially as we may have taken the technology to its limits.
Replacing Lithium Batteries with Abundant Metals
Ideally, we should be using common metals like copper and iron which are available in abundance and cheaper to mine. China is using lithium batteries with iron-rich materials, including using lithium-iron-phosphates as cathodes in its electric buses.
These electrodes are robust and can recycle many times. However, they are less dense, and therefore require twice the number of calls as lithium-ion batteries. Lithium-manganese-oxide cathodes have similar limitations. Lithium-manganese-niobium-oxyfluoride has made a breakthrough at research level. However, it is unsafe in the current version, because it needs high-voltage electricity for charging.
Therefore, Conversion Materials Seem the Best Alternative
Converging materials involves synthesizing two or more kinds into a new product. There are two types of costs to this, namely prime and conversion outlays. Nature.com believes this is the most promising way forward.
They cite the example of copper and iron fluorides and silicon reacting successfully with lithium ions. “A transition metal in a conversion cathode can host up to six times more lithium atoms than in a standard cathode,” they say. Because such materials swell more to accommodate the extra lithium atoms.
Could the Way Forward Involve Silicon-Based Anodes?
Nature.com favors replacing lithium batteries with this approach. Since we obtain silicon from abundant sand, and it stores ten times more lithium-ions than graphite, by weight. “Combining conversion cathodes with silicon anodes in the next generation of lithium-ion battery cells could allow cells to store more than twice as much energy as the best conventional ones by volume,” they say. “And more than three times by weight.
“Half as many cells would therefore be required to power electric vehicles, also halving costs, weight, and volume,” they add. We explore how this is working in practice in the next post.
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Longer Lasting Rechargeable Lithium Batteries with Silicon Electrodes
Making Anodes from Silicon Scrap
Preview Image: Silica in One of Its Many Lovely Forms, Sandstone