In situ formation of liquid crystal interphase in electrolytes with soft templating effects for aqueous dual-electrode-free batteries

Abstract

Zn/MnO2 batteries, driven by a dual deposition reaction, are a prominent avenue for achieving high energy density in aqueous systems. Introducing an initially dual-electrode-free (anode/cathode) configuration can further boost energy density to over 200 Wh kg−1, but with limited cycle life due to the poor reversibility of Zn/MnO2 deposition and stripping. Drawing inspiration from soft templating strategies in material synthesis, here we apply this approach to electrodeposition and stripping by designing an in situ formed liquid crystal interphase. This concept is achieved by incorporating just 0.1 mM of surfactant molecules into the electrolyte, which induces favourable c-axis orientations in depositing both hexagonal Zn and MnO2. This enhancement subsequently increases the deposition/stripping reversibility and promotes the cycle life of the dual-electrode-free battery, achieving 80% capacity retention after ~950 cycles. This liquid crystal interphase chemistry also holds great promise for regulating deposition in other crystal systems, opening an exciting research direction for next-generation high-energy-density and long-duration energy storage based on aqueous chemistries. Achieving long-cycle-life, aqueous, dual-electrode-free Zn/MnO2 batteries with high energy density is challenging. This work introduces a liquid crystal interphase in the electrolytes with soft templating effects, considerably enhancing performance.