Mechanistic insights into electric fish-inspired power sources: A combined modeling and experimental approach

Soft-material power sources inspired by strongly electric fish have attracted significant attention for their ability to generate electric potential with sufficient power density, making them suitable for safe integration with biological systems and flexible electronics. Although various experimental studies have demonstrated the feasibility of this bioinspired power generation mechanism, key challenges, such as resistance to self-discharge and electrode interactions, remain underexplored. Addressing these challenges requires a deeper understanding of the functional roles of each system component and the underlying physics of their interactions. To investigate these limitations at a component level, we use a finite element model based on the Nernst–Planck and Butler–Volmer equations, which govern ion transport and electrode interactions in electrochemical cells. By visualizing ion movement and parameter influence on electrical performance, we provide insight into phenomena often challenging to quantify directly through experiments. Our findings reveal that increasing the fixed charge concentration in the selective layers increases discharge duration by nearly six-fold. We also identified key sources of inefficiencies related to ionic mobility and charge capacity at the electrode–electrolyte interface. Through experimental validation, we derive key input parameters from hydrogel-based electrochemical cells and formalize experimental protocols to improve data reliability, including equilibrating hydrogel layers at constant relative humidity. Additionally, we characterize the performance of electric fish-inspired power sources with battery-relevant metrics such as power density, discharge duration, and cycle life. Our approach provides a systematic framework for prototyping and improving electric fish-inspired power sources, informing critical design decisions, and advancing next-generation energy storage solutions.