Cheap storage is an important missing link to make solar PV really take off. Wood may be the unlikely material that make battery technology cheap enough.
Sodium is chemically similar to lithium, but because sodium ions are five times the size of lithium ions it is unfortunately not practical in batteries. That is because a battery works by shuttling ions between its anode and its cathode. With the bigger ions the more damage is caused, which shortens the battery’s life.
For this reason, sodium are not being used in batteries. However, as it is abundant and thus cheaper sodium is an attractive solution.
Tests with wood
Scientists may now have found a way to get around this challenge. Instead of using metal electrodes, tests have been done with treated wood as conductor.
The idea is that suitably treated wood could do the job of conduction equally well while providing more yielding support for an electrode that was continually expanding and contracting as ions moved in and out of it.
Wood from yellow pine applied with a film of tin to each sliver. The slivers were immersed in an electrolyte containing sodium ions and the resulting battery were put through 400 cycles of discharging and recharging.
The test results where promising, which make wood a plausible candidate for battery frames.
You are not likely to see wooden-framed batteries in your phone or laptop anytime soon.
The idea is to make big sodium-ion batteries for overnight storage of electricity from solar PV power stations.
That will create a massive boost to the solar power industry.