Invention: Slimline radioactive battery
Engineers have long hoped to exploit radioactive decay to generate electricity. One way to do this is to use a radioactive isotope, such as a variant of hydrogen called tritium, that emits electrons as it decays. Current is generated when the electrons hit semiconductive material nearby.
Attempts to put the theory into practice have been plagued by extremely low efficiency, though, converting only a small fraction of the emitted electrons into current.
The problem is that the electrons cannot travel far from their starting place in the tritium nucleus. Most end up lodging in the radioactive material itself and never reach the adjacent semiconductor.
Now Paul Engel and colleagues at Rice University in Houston, Texas, say that these batteries can be made more efficient by using a thin layer of a liquid polymer that contains the isotope.