Betavoltaics is the use of energy by the decay of radioactive isotopes to generate electric current. Electricity is typically obtained from the radioactive decay of sources such as tritium and the release of beta particles, or electrons (Betavoltaics-Wikipedia). These devices are typically used for long term and/or remote energy and are able to last for decades. Betavoltaic energy supplies can be made very small, and thus can be employed in mobile devices typically for critical applications. Types of uses include surveillance planes and missiles and their tamper-proof memory chips used in militaries (Technology Review,  09/10/2010).

Betavoltaics research ranges for areas of military sensors for property, hardware, as well as medical applications and sensor applications. Typically, these are high energy density devices, or devices that are capable of running for many decades. A possible application in medical implants could be made by Widetronix, a company developing betavoltaic devices. These devices use a very weakly radioactive material called tritium, which has the radioactive shielding requirements of a piece of paper.

Betavoltaic are not currently capable technologically of generating large amounts of electrical energy for items that require constant amounts of energy. Betavoltaics are best for small items, such as small batteries in custom engineered devices and sensors, as well as radio equipment. These devices require microwatts of power to send radio signals. But applications of a military tamper-proof memory circuit for missiles, etc. is being developed by Widetronix, and can be produced in a year's time. According to Amit Lal, embedded sensors could also be used on betavoltaic energy which could last 100 years (Technology Review, 09/10/2010). The prospects of producing devices on betavoltaics for mobile and even computing technologies are a possibility, and may be developed if an infrastructure for nuclear radioisotopes and nuclear energy is developed by such companies as Widetronix (Technology Review, 09/10/2010).  

Technology Review, http://www.technologyreview.com/energy/23959/page2/

Betavoltaics, http://en.wikipedia.org/wiki/Betavoltaics#Applications