Chemistry - Atomic battery

The term atomic battery or nuclear battery is the commonly used term to describe a device which uses the charged particle emissions from a radioactive isotope to directly electrically charge a circuit or cause a mechanical movement on a microscopic scale due to electrostatic charge buildup effects.

Contents

1 Mechanism of Energy Production

2 Radioisotopes Used

3 Reciprocating Electromechanical Atomic Batteries

4 External links

5 See Also

Mechanism of Energy Production

Atomic batteries are often confused with radioisotope thermoelectric generators, both of which produce electricity using the energy of radioactive decay, but each using different means to do so. Though the definition for an atomic battery is not strict and it may not necessarily be erroneous to call an RTG an atomic battery. In an atomic battery beta particles (or sometimes more rarely alpha particles) emitted by a radioisotope are collected by an electrode and cause it to gain an electric charge. The radioisotope, after releasing some of these particles, develops the opposite charge and thus the difference in charge between the two plates can be used to produce an electric current. This mechanism of oppositely charged electrodes is exactly like how a conventional battery or capacitor produce electricity, except these use chemical or static energy respectively, while the atomic battery uses nuclear energy. Atomic batteries could produce far more energy over time then a conventional battery and could continue working for decades. Unfortunately a large drawback is that atomic batteries produce only nano or micro watts of power per cm² of electrode area, while a conventional battery can produce up to watts of power per cm^{2. This means atomic batteries either have to be made very large out of hundreds or thousands of plate arrays, or must be used to trickle charge a conventional battery or capacitor. Atomic batteries usually have an efficiency of .1-5%. Atomic batteries have found limited uses outside of research.}

Radioisotopes Used

Atomic batteries use radioisotopes that produce low energy beta particles or sometimes of varying energies alpha particles. Low energy beta particles are need ed to prevent the production of high energy penetrating Bremsstrahlung radiation that would require heavy shielding. Radioisotopes such as Tritium, Nickel-63 and Promethium-147 have been tested. Plutonium-238 may have also been tested.

Reciprocating Electromechanical Atomic Batteries

Electromechanical atomic batteries use the build up of charge between two plates to pull one bendable plate towards the other, until the two plates touch, discharge, equalizing the electrostatic buildup, and spring back. The mechanical motion produced can be used to produce electricity through flexing of a piezoelectric material or through a linear generator. Milliwatts of power are produced in pulses every few minutes or seconds depending on the charge rate.