Transcript
Researchers at the University of California Riverside have made
another breakthrough in energy research: They have created a lithium ion
battery that outperforms the current industry standard by 300 percent.
As they reported in the journal Nature Scientific Reports,
this discovery represents a low-cost, non-toxic,
environmentally-friendly way to produce high-performance lithium ion
battery anodes - and the key ingredient is sand.
Graphite is the current standard material for anodes, but as
electronics have become more powerful, graphite's ability to be improved
has been virtually tapped out.
Researchers are now focusing on using silicon at the nanoscale level
as a replacement for graphite. The two problems with nanoscale silicon
are that it degrades quickly and is hard to produce in large quantities.
The researchers set out to solve both of these problems. After
searching for sand with an extremely high percentage of quartz, they
found it at the Cedar Creek Reservoir, east of Dallas.
The lab at UC Riverside milled the sand down to the nanometer scale,
and used a series of purification steps. Then, they ground salt and
magnesium into the purified quartz. The resulting powder was heated. The
salt acted as a heat absorber and the magnesium worked to remove the
oxygen from the quartz; this resulted in pure silicon.
The pure nano-silicon formed in a very porous 3-D sponge-like
consistency. And, that porosity has proven to be the key to improving
the performance of the batteries built with the nano-silicon.
The improved performance could mean expanding the expected lifespan
of silicon-based electric vehicle batteries by 300 percent or more,
which would be significant for consumers, since replacement batteries
cost thousands of dollars. For cell phones or tablets, it could mean
having to recharge every three days, instead of every day.
Now, the team is working to produce larger quantities of the
nano-silicon beach sand while moving from coin-size batteries to the
pouch-size batteries that are used in cell phones.
|
