Betavoltaic microbatteries using TiO2 nanotube arrays

This paper reports a betavoltaic microbattery using crystallized and vertically oriented nanotube arrays based on wide band-gap semiconductor TiO₂. A sandwich-type metal/TiO2 nanotube (TNT) array/metal structure under build-in contact potential difference was used to investigate betavoltaic effect. The sandwiched structure is integrated by immobilized TNT arrays on Ti foil with radioisotope 63Ni planar source on Ni substrate (Ni-⁶³Ni/TNT array/Ti). Under irradiation of the ⁶³Ni source with activity of 8 mCi, the structure presents optimum energy conversion efficiency of 7.30% with open-circuit voltage of 1.54 V and short-circuit current of 12.43 nA. The TNT arrays exhibit a great potential for developing betavoltaic batteries due to its excellent capacities in capture of beta particles and transportation of carriers.