An Ultrastable Presodiated Titanium Disulfide Anode for Aqueous Rocking-Chair Zinc Ion Battery

Rechargeable aqueous Zn-based batteries are attractive candidates as energy storage technology, but the uncontrollable Zn dendrites, low stripping/plating coulombic efficiency, and inefficient utilization of Zn metal limit the battery reliability and energy density. Herein, for the first time, a novel presodiated TiS2 (Na0.14TiS2) is proposed and investigated as an intercalated anode for aqueous Zn-ion batteries, showing a capacity of 140 mAh g(-1) with a suitable potential of 0.3 V (vs Zn2+/Zn) at 0.05 A g(-1) and superior cyclability of 77% retention over 5000 cycles at 0.5 A g(-1). The remarkable performance originates from the buffer phase formation of Na0.14TiS2 after chemically presodiating TiS2, which not only improves the structural reversibility and stability but also enhances the diffusion coefficient and electronic conductivity, and lowers cation migration barrier, as evidenced by a series of experimental and theoretical studies. Moreover, an aqueous rocking-chair Zn-ion full battery is successfully demonstrated by this Na0.14TiS2 anode and ZnMn2O4 cathode, which delivers a capacity of 105 mAh g(-1) (for anode) with an average voltage of 0.95 V at 0.05 A g(-1) and preserves 74% retention after 100 cycles at 0.2 A g(-1), demonstrating the feasibility of Zn-ion full batteries for energy storage applications.