Team finds major storage capacity in water-based batteries

This article reports recent advances in the development of metal-free, water-based batteries as a safer and more sustainable alternative to conventional lithium-ion systems. Researchers at Texas A&M University investigated redox-active, non-conjugated radical polymer electrodes in aqueous electrolytes and identified up to a 1,000% variation in energy storage capacity as a function of electrolyte composition. The study emphasizes the critical role of electrolyte choice—specifically its chao-/kosmotropic character—in governing electrode swelling, ion conduction, and overall electrochemical performance. Experimental characterization employed electrochemical quartz crystal microbalance with dissipation monitoring over multiple timescales to quantify the coupled transport of electrons, ions, water, and salt during battery operation. These measurements were complemented by molecular-scale simulations that modeled electrodes at different states of charge, providing detailed insight into the structure, dynamics, and solvent–electrode interactions that drive water and ion insertion. The combined theoretical and experimental findings elucidate the mechanisms underlying performance differences among aqueous polymer electrodes and demonstrate that appropriate electrolyte design can dramatically enhance capacity while mitigating safety risks such as battery fires. This work advances the fundamental understanding of metal-free aqueous energy storage systems and offers design principles that could support domestically sourced, lithium- and cobalt-free battery technologies with improved safety and supply-chain robustness.