The proposed innovation will significantly improve the performance of tritium-powered betavoltaic batteries through the development of a high bandgap InAlP diode coupled to a high beta-flux thin film metal tritide. Tritium has a power density of 300 W/kg and City Labs’ new metal hydride film has a power density approaching 70 W/Kg and can be expanded to 100 W/kg.This project will investigate the performance improvement from a wide bandgap semiconductor diode, specifically with the goal of achieving >10% beta-electron energy conversion efficiency. The device will be built by City Labs with its tritium beta emitter expertise and MicroLink's metalorganic chemical vapor deposition (MOCVD) capability.
The proposed Phase I research seeks to develop an InAlP p/n junction with a high beta-flux metal tritide for use in betavoltaic power sources. The betavoltaic p/n junction will increase the efficiency of betavoltaic devices from 8% up to 12% based on the incident tritium beta flux. The secondary goal is to investigate the release of the betavoltaic epitaxial layer through the removal of the substrate via lapidary and/or chemical etchants.
City Labs anticipate that the proposed work will result in the creation of a betavoltaic battery with a volumetric energy density 100 times that of lithium batteries (integrated over 20 years of continuous power). This ultra-high, energy density will allow tritium betavoltaics to be introduced to a mainstream market in a number of potential NASA applications, including high value deep space missions, CubeSats, independent power sources for spacecraft electronics and backup communications systems
Applications include: defense/security applications, anti-tamper, nuclear storage/ device monitoring applications, satellite power supplies, including CubeSats, autonomous wireless sensors, and medical bionics/ implants. City Labs has sold prototype and commercial batteries into select high value markets with customers such as Lockheed Martin and NASA's JPL and currently has letters-of-support from Orbital ATK and Lockheed Martin Space Systems for the proposed betavoltaic power source.