A Near 0 V and Low-Strain Intercalative Anode for Aqueous Zinc-Ion Batteries

Metallic Zn anodes exhibit uncontrollable dendrites,impracticallylow Zn utilization, hydrogen evolution, and unexpected byproducts,limiting the practical process of aqueous zinc-ion batteries (AZIBs);thus, exploring alternative insertion anodes has become a reasonablestrategy, exemplified by the successful application of graphite anodesin lithium-ion batteries. However, the current intercalative anodesare still plagued by high Zn2+ insertion potential andinadequate cycle life, and the alternative choice is quite limited.Here, we report a polyanionic insertion anode (Ti2O(PO4)(2)& BULL;2H(2)O) that shows an extremelylow insertion potential of 0.07 V with a reversible capacity of 124.6mAh g(-1). This anode possesses a robust and spaciousframework, demonstrating high reversibility with low strain duringcycling. Coupled with a KZnHCF cathode, a 1.6 V "rocking-chair"full battery is achieved with an ultralong life of 5000 cycles, surpassingthe reported congeneric batteries. This work shares a new vision forthe development of practical AZIBs.