Multiple Cations Nanoconfinement in Ultrathin V₂O₅ Nanosheets Enables Ultrafast Ion Diffusion Kinetics Toward...

Nanoconfinement of cations in layered oxide cathode is an important approach to realize advanced zinc ion storage performance. However, thus far, the conventional hydrothermal/solvothermal route for this nanoconfinement has been restricted to its uncontrollable phase structure and the difficulty on the multiple cation co-confinement simultaneously. Herein, this work reports a general, supramolecular self-assembly of ultrathin V₂O₅ nanosheets using various unitary cations including Na⁺, K⁺, Mg²⁺, Ca²⁺, Zn²⁺, Al³⁺, NH₄ ⁺, and multiple cations (NH₄ ⁺ + Na⁺, NH₄ ⁺ + Na⁺ + Ca²⁺, NH₄ ⁺ + Na⁺ + Ca²⁺ +Mg²⁺). The unitary cation confinement results in a remarkable increase in the specific capacity and Zn-ion diffusion kinetics, and the multiple cation confinement gives rise to superior structural and cycling stability by multiple cation synergetic pillaring effect. The optimized diffusion coefficient of Zn-ion (7.5 × 10^-8 cm² s^-1) in this assembly series surpasses most of the V-based cathodes reported up to date. The work develops a novel multiple-cations nanoconfinement strategy toward high-performance cathode for aqueous battery. It also provides new insights into the guest cation regulation of zinc-ion diffusion kinetics through a general, supramolecular assembly pathway.