Liquefied zinc-anodes for flexible fuel cells and reversible flow cells

With the high capacity brought by the external liquid tanks, fuel cells and flow cells have shown positive application prospects as power batteries and energy storage batteries, respectively. However, low power density and low volume energy density are the bottlenecks limiting their commercialization. Herein, a GaInSn-liquefied Zn-metal strategy has been proposed for developing high-performance room temperature aqueous liquid fuel cells and rechargeable flow cells. Among them, GaIn alloy was used to dissolve Zn metal, and Sn was used to improve the corrosion resistance of the liquid alloy. At room temperature, the developed liquid fuel cell exhibited a peak discharge power density of up to 78.792 mW cm⁻², good low-temperature start-up property, flexibility, and elasticity. Moreover, through the design of a dual circulation operating mode of liquid metal anode and electrolyte, the liquid metal−air flow cell showed stable discharging and charging performance for over 30 h at current densities of 25 mA cm⁻² and 15 mA cm⁻², respectively. The concept of “liquid reaction−solid energy storage” has been realized: the flowing anode enables real-time updating of metals and participates in electrochemical reactions in liquid phase; The external Zn metal immersed in saturated liquid metal achieves an increase in the volume energy density of the electrochemical cells in solid form.