Long-lasting radioluminescent batteries now 10 times more efficient

The long lifetimes and high power density of radioluminescent batteries make them an attractive power source for monitoring systems in deep sea and space. However, low output power and energy conversion efficiency impede their practical application.

Zhao et al. designed and fabricated an X-ray radioluminescent battery with an output power density of 13.4 µW/cm² and an energy conversion efficiency of 1.28%, which is 10 times better than the previous best reported value of 0.12%.

They employed three strategies to improve the efficiency of radioluminescent batteries. To reduce backscattering loss and self-absorption loss, they used X-ray energy sources instead of conventional beta-radioactive sources.

Radioluminescent batteries feature scintillators or phosphor layers, which are luminescent and convert radiation decay energy into optical energy. Instead of the more commonly used zinc sulfide-based phosphor, the authors based their battery on cerium-doped Gd₃Al₂Ga₃O₁₂, or GAGG:Ce, a single-crystal scintillator. Single-crystal scintillators exhibit less scattering loss than phosphors.

Radioluminescent batteries also consist of photovoltaic batteries that convert optical energy into electrical power. The authors were able to optimize efficiency by matching the bandgap of the battery to the luminescence spectrum of the scintillator, GAGG:Ce.

“The performance breakthrough achieved in our work takes the commercial application of this type of battery a big step forward,” said author Yiying Zhao.

The authors plan to explore potential applications of their radioluminescent battery, including wireless sensor networks, online monitoring systems, micro-electromechanical systems, and implanted medical devices.

Source: “Ten-fold efficiency improvement of X-ray radioluminescent batteries basing on GAGG:Ce single crystal scintillators,” by Chen Zhao, Jiwei Ren, Lin lei, Feiyi Liao, Xianglei Shi, Dayong Zhou, Kezhao Liu, and Yiying Zhao, Applied Physics Letters (2021). The article can be accessed at https://aip.scitation.org/doi/full/10.1063/5.0073048 .