Evaluation of a Silicon 90Sr Betavoltaic Power Source.

Jefferson Dixon,Dusan Coso,Aravindh Rajan,Shannon Yee,Ajeet Rohatgi,Ajay D Upadhyaya,Arun Majumdar,Steven Bohlemann,Steven Chu

doi:10.1038/srep38182

Jefferson Dixon, Dusan Coso + Show 7 more

Open Access

https://doi.org/10.1038/srep38182

Copy DOI

Abstract

Betavoltaic energy converters (i.e., β-batteries) are attractive power sources because of their potential for high energy densities (>200 MWh/kg) and long duration continuous discharge (>1 year). However, conversion efficiencies have been historically low (<3%). High efficiency devices can be achieved by matching β-radiation transport length scales with the device physics length scales. In this work, the efficiency of c-Si devices using high-energy (>1 MeV) electrons emitted from 90Sr as a power source is investigated. We propose a design for a >10% efficient betavoltaic device, which generates 1 W of power. A Varian Clinac iX is used to simulate the high-energy electrons emitted from 90Sr, and a high efficiency c-Si photovoltaic cell is used as the converter. The measured conversion efficiency is 16%. This relatively high value is attributed to proper length scale matching and the generation of secondary electrons in c-Si by the primary β-particles.

Highlights

The concept of a nuclear battery has attracted researchers since the 1950s because of the potentially long duration of continuous discharge[1]
We revisit the mechanisms involved in betavoltaic power generation and consider ways to improve the efficiency to levels exceeding 10%
To evaluate an appropriate source material, we considered over 400 isotopes based on their maximum β-particle energies, half-lives, maximum specific power, decay products/daughters, and availability

Summary

Introduction

The concept of a nuclear battery has attracted researchers since the 1950s because of the potentially long duration of continuous discharge[1]. There is a mission need to revisit nuclear battery concepts with a target power generation of ~1 W. Alphavoltaics and betavoltaics rely on α and β-particles generated by their respective source materials to produce electric power through the direct conversion of the particles’ kinetic energy. Α-particles are emitted at greater energies than β-particles and alphavoltaics have the potential for higher power densities. The commercial viability of alphavoltaics is reduced by the imposition of strict regulations on α-emitters (e.g., special nuclear materials). In 2011, City Labs, Inc. was given the first general license to manufacture and distribute tritium betavoltaics operating in the nanowatt range for low power applications[8]. We discuss how this can be achieved in a device, and experimentally demonstrate high efficiency conversion using a simulated β-particle emitting source

Methods

Results

Conclusion