Ti2O3(H2PO4)2·2H2O as a Novel Intercalated Anode for Ultralong Lifespan "Rocking‐chair" Aqueous Zinc‐ion Batteries

The application of aqueous zinc‐ion batteries (AZIBs) with Zn metal anode is hindered by severe dendritic growth, corrosion, and inefficient Zn utilization. "Rocking‐chair" type AZIBs are considered a viable approach toward practical applications due to the success of commercial lithium‐ion batteries employing intercalated graphite anodes. Herein, a new type of layered titanium phosphate Ti2O3(H2PO4)2·2H2O is proposed for the first time as the intercalated anodes for AZIBs, exhibiting a capacity of 108 mAh g‐1 at 50 mA g‐1, with a low discharge potential of 0.17 V (vs. Zn2+/Zn). The ion insertion process was thoroughly investigated, and a micro‐dendrite growth‐corrosion mode was proposed to explain the capacity degradation mechanism. Corresponding countermeasures were designed, resulting in a significant improvement in cycle life. When coupled with zinc hexacyanoferrate (KZnHCF) cathode, the "rocking‐chair" full battery exhibits an ultralong lifespan of 50000 cycles (111 days) at 2.0 A g‐1 with 94% capacity retention. This work presents a novel perspective for the development of practical AZIBs.