The multifunctional use of an aqueous battery for a high capacity jellyfish robot.

Liu, Xu; Jin, Shuo; Shao, Yiqi; Kuperman, Sofia; Pratt, Autumn; Zhang, Duhan; Lo, Jacqueline; Joo, Yong Lak et al. · Sci Adv · 2024

basic_science · Level V

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Abstract

The batteries that power untethered underwater vehicles (UUVs) serve a single purpose: to provide energy to electronics and motors; the more energy required, the bigger the robot must be to accommodate space for more energy storage. By choosing batteries composed primarily of liquid media [e.g., redox flow batteries (RFBs)], the increased weight can be better distributed for improved capacity with reduced inertial moment. Here, we formed an RFB into the shape of a jellyfish, using two redox chemistries and architectures: (i) a secondary ZnBr<sub>2</sub> battery and (ii) a hybrid primary/secondary ZnI<sub>2</sub> battery. A UUV was able to be powered solely by RFBs with increased volumetric (<i>Q</i> ~ 11 ampere-hours per liter) and areal (108 milliampere-hours per square centimeter) energy density, resulting in a long operational lifetime (<i>T</i> ~ 1.5 hours) for UUVs composed of primarily electrochemically energy-dense liquid (~90% of the robot's weight).