Multiple Cations Nanoconfinement in Ultrathin V 2 O 5 Nanosheets Enables Ultrafast Ion Diffusion Kinetics Toward High-performance Zinc Ion Battery.

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 V 2 O 5 nanosheets using various unitary cations including Na + , K + , Mg 2+ , Ca 2+ , Zn 2+ , Al 3+ , NH 4 + , and multiple cations (NH 4 + + Na + , NH 4 + + Na + + Ca 2+ , NH 4 + + Na + + Ca 2+ +Mg 2+ ). 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 cm 2 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.