Organic/inorganic functional Janus separator for high-performance zinc anode

Abstract

Aqueous Zinc-ion batteries have been a promising candidate for large-scale energy storage system benefiting from its economic, high safety and energy density. Whereas, the issues of Zn anode that surrounding dendrite growth, side reaction and corrosion have hindered it from further practical application. To circumvent these problems, we propose an organic/inorganic functional Janus separator based on commercial glass fiber (GF) membrane, effectively inhibiting the growth of Zn dendrite and enhancing the reversibility of Zn anode. The functional layer with dense and tiny pore, can restricts ion diffusion, and the filler of Graphene oxide- Titanium dioxide (GO-TiO₂) could induce the Zn²⁺ epitaxial deposition. The Zn symmetric cell with the modified separator runs over 2000 h stably at a density of 1 mA cm⁻² (1800 h, 2 mA cm⁻²). Even at a higher density of 5 mA cm⁻², it also shows an ultralong lifespan of over 600 h. When assembled into Zn//MnO₂ full cell, the modified separator shows higher capacity (initial capacity of 112.1 mAh g⁻¹) and capacity retention (60.57 % after 500 cycles at 1C) than GF (97.1 mAh g⁻¹, 48.4 %). Furthermore, the full cell with the modified separator possesses more excellent rate performance. This novel modification strategy of separator opens up more possibilities for high-performance aqueous Zn-ion batteries.