Bioelectronics come to mind. Pacemakers, glucose monitors and insulin injectors. Prosthetics too. What's that? Oh yes! Mom's hearing aids. To mention just a few. Who said cellphones? Build the fab onsite a solar farm, so we can use the sun to arm the radiobling, while using up those half-dead nuclear C14 things.

There are a few things missing in this article. Did they achieve an interesting energy density, or is the output minuscule?
A simple watts per pound figure would be nice. I know the traditional measure is not useful since they can produce the same output indefinitely, but volts and amps per second would help understand the possible applications.
Assuming the output power is useful it would be very useful for space applications where the normal batteries are too limited in lifetime and durability, and the radio decay power source like curiosity uses too problematic. Of course implants would also be a useful application as it could solve one of the more challenging problems of powering the device long term.

Wondering if it would be possible to use these batteries to produce small lamps that could be implanted into rural roads and byways to provide safer driving for travellers

Yeah, it's a bit tough to come up with ideas, as the University is asking for, when they don't tell you what kind of mass would be required to power even a single LED, and at what cost. It's all a very fascinating prospect though. The idea of satellites and small spacecraft that have effectively unending power without the need to recharge is amazing. Could you manufacture a utility pole that is able to power a street light? For high security (think Pentagon) or medical uses, just how much to power a computer?
While the idea of using this in small devices like cellphones and hearing aids is tempting, I can't help but think that the cost would be too high for such uses, and we probably don't want such materials to be considered disposable.

Agree, we would have to know the output potential of these diamond batteries and whether they could, in effect, be arranged in series or parallel to multiply what looks to be very small voltage/amperage. The size and weight of the finished package will always be a consideration.

...small electric current?
Size, weight, wattage? ............PLEASE! +/- Connection method used? ............PLEASE!

VirtualGathis is quite correct- the unanswered question is energy density. This is a fascinating concept, but is it scalable to anything useful?
BTW, the term battery in this application is incorrect- this device is more properly termed a generator.

The decay energy is 156keV, times 6.02e23 divided by 14 gives about 1GJ/g, but 1g of C-14 will give off half that energy over 5730 years, so about 3mW/g C-14 if efficiency were perfect, realistically for the whole device it might be one or two tenths of that. So something like 5 pounds per watt.

...sounds like a great idea, but diamond is carbon and can burn in a fire, releasing beta decay radiation into the air and environment-- although I can see the merit in a fireproof application.

This sounds great and all, but we got e-cigs, samsung phones, and a host of other shit blowing up in peoples pockets because you can't contain those simple batteries! Get that right then ill stick one of these in my pocket next to my johnson.