Radiation-induced separation and accumulation of electric charge in supercapacitors

In current sources with a radioactive isotope (CSRI), nuclear energy is directly converted into electricity due to the separation of electric charges during the decay of radioactive isotopes. It was previously shown that asymmetric supercapacitors can be used as CSRI prototypes if, after being exposed to pulsed reactor irradiation, the electric charge on their plates increases to several coulombs as a result of internal induced activity. In this paper, the electric charge separation and accumulation in supercapacitors were studied directly in the process of neutron irradiation. The study was focused on the electrophysical characteristics of cylindrical supercapacitors with an organic electrolyte produced by JSC “ELEKOND”. A comparison of symmetric and asymmetric supercapacitors showed that an effective charge accumulation occurs in the asymmetric capacitors: it is independent of the neutron flux density and determined by the absorbed radiation dose. The electrical voltage between the plates of a symmetrical supercapacitor with a capacity of 100 F during irradiation up to an absorbed dose of 50 Gy reaches 1.24 mV. When asymmetric supercapacitors are irradiated with the same dose, a significant increase in the potential difference up to 1.15 V is observed during irradiation and for a long time afterwards (1.5·105 s) due to the electric charge redistribution (~ 5·10–3 C) in the electrolyte and carbon particles with the formation of a double electrical layer. The post-radiation increase in the capacity of asymmetric supercapacitors is ~ 5 mF.