662 IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 60, NO. 2, APRIL 2013 The Potential of Using Li-Ion Batteries for Radiation Detection Jie Qiu, Lei Cao, Senior Member, IEEE, Padhraic Mulligan, Danyal Turkoglu, Shrikant C. Nagpure, Marcello Canova, and Anne Co Abstract—This work describes the measurement of the change in current of two types of Li-ion batteries, both commercial off-the- shelf and in-house-assembled coin cells, under radiation exposure. The discharging batteries were irradiated with a neutron beam with a 30-mm diameter (adjustable to 10 mm and 5 mm) using the Ohio State University Research Reactor and was measured for the change of electric current with a Keithley SourceMeter. We have observed an increase in current when the batteries were exposed to gamma rays and a decrease in current when only thermal neu- trons were applied. We discussed the mechanisms that are respon- sible for inducing such changes, including the electrode polariza- tion caused by irradiation. The immediate application of a single coin cell in a current mode can be a small neutron or gamma-beam monitor or a near-core flux monitor in a high-flux environment. Index Terms—Coin cell, flux monitor, Li-ion battery, neutron sensor, radiation detection. I. INTRODUCTION W ITH mobile devices becoming ubiquitous, lithium-ion (Li-ion) batteries are becoming the power source of choice, owing to their high energy and power density. Given the inherent sensitivity of Li to neutrons, Li-ion cells have great potential as unattended neutron detectors, either individually or on a large and inexpensive scale. Recent examples of mobile devices used as unattended radiation detectors [1] such as the utilization of a CCD/CMOS camera in a smartphone or a small Geiger-Müller tube (GM tube) attached to an iPhone [2] are real-world implementations of the concept of an unattended radiation detection network. The Li isotope has a natural abundance of 7.4% and a thermal neutron absorption cross sec- tion of 940 barns [3]. Upon neutron absorption, Li splits into a triton H and an alpha particle He . The depletion of Li following neutron absorption and the creation of two energetic charged particles would, in theory, disrupt the capacity and Manuscript received June 15, 2012; revised October 15, 2012; accepted November 26, 2012. Date of publication January 15, 2013; date of current version April 10, 2013. This work was supported in part by the seed grant from the Institute for Materials Research at The Ohio State University. J. Qiu, L. Cao, P. Mulligan, and D. Turkoglu are with the Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, Ohio State University, Columbus, OH 43210 USA (e-mail: cao.152@osu.edu). S. C. Nagpure and M. Canova are with the Center for Automotive Research, Department of Mechanical and Aerospace Engineering, Ohio State University, Columbus, OH 43210 USA. A. Co is with the Department of Chemistry, Ohio State University, Columbus, OH 43210 USA. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TNS.2012.2231097 power capabilities of the battery, resulting in premature battery aging. Commercially available Li-ion cells typically use a Li metal oxide cathode, such as LiMnO or LiFePO , and a graphite or Li metal as the anode. The electrodes are bonded between two cur- rent collectors using a binding agent, typically polyvinylidene fluoride. A thin layer of microporous polymer film separates the anode from the cathode electrically, allowing for the passage of ions through the electrolyte solution. During discharging oper- ations, Li ions de-intercalate from the anode and migrate to the cathode through the liquid phase. The migration of Li inside a Li-ion battery has been recently studied using a neutron depth profiling method [4], [5]. This technique allows one to obtain quantitative results in terms of the Li distribution in the cath- odes and anodes of cells. If the Li concentration inside a Li-ion battery can be inten- tionally measured by a neutron beam, it is logical to investigate whether a Li-ion cell can be used as a neutron sensor, namely whether neutrons could produce significant changes in the elec- trical performance of the cell. In addition to neutrons, gamma radiation may be more detectable by Li-ion batteries because of its direct interaction with an atom’s extranuclear electrons. Fur- thermore, electrolyte decomposition may occur under gamma radiation, leading to the catalyzation of solid-electrolyte inter- phase (SEI) formation. Mechanisms that may determine the pos- sible changes of current when a Li-ion battery is exposed to ra- diation are: 1) One neutron-capture event consumes one Li atom. 2) The slowing down of two energetic charged particles (an alpha particle and a triton) created by neutron capture will ionize the elements within the battery materials in cascade mode and may disturb the electrical equilibrium. 3) The alpha particles will eventually become helium gas, the accumulation of which, under high neutron flux, may cause a sealed battery to swell or lead to structural damage. 4) Excess electrons and ions will be produced by gamma-ray ionization. In general, there is an interest in understanding and character- izing the electronic response of Li-ion battery materials to neu- trons and gamma radiation. In this study, the effects of neutron and gamma irradiation on the change of the current amplitude of Li-ion batteries are investigated. This may lead to using Li-ion battery-powered devices for radiation detection in a large scale. Alternatively, an immediate application would be a high-field radiation beam or flux monitor using a single cell working in a current mode. 0018-9499/$31.00 © 2013 IEEE