Aqueous Nickel-Ion Batteries with Long Lifetime, High Capacity, and High Rate Capability Based on K₂V₆O₁₆·1.64H₂O Cathodes

Abstract

Aqueous nickel-ion batteries (NiIBs) featuring small ionic radius and high theoretical volumetric capacity hold great potential in novel aqueous battery systems. However, the further development of aqueous NiIBs is plagued, owing to the strong electrostatic repulsion between Ni2+ ions and the host electrode materials, leading to the limited capacity, poor cycling performance, and inferior rate capability. Herein, the novel K2V6O16·1.64H2O (KVO) nanobelts are synthesized and utilized as cathodes for aqueous NiIBs. The KVO cathode delivers a highly reversible specific capacity of ∼140.0 mA h g–1 after the initial activation process, and ∼70.8 mA h g–1 is achieved with the Coulombic efficiency close to 100% at 0.2 A g–1 after 1000 cycles. ∼40.5 mA h g–1 is still achieved at 1.0 A g–1 after 8000 cycles. Moreover, this battery possesses a remarkable rate capability with ∼137.4 mA h g–1 being regained when the current density is switched from 1.8 to 0.2 A g–1, which is ∼97% of that at 0.2 A g–1. The capacity, lifetime, and rate capability achieved all far exceed those of the reported aqueous NiIBs, arising from the layered structure and fast kinetics of the KVO cathode. This work paves the way toward the design of aqueous NiIBs with high electrochemical performances.

LiV3O8 as an intercalation-type cathode for aqueous aluminum-ion batteries

“…18 In addition, the inbuilt characteristic multiple-oxidation-state feature of vanadium has been shown to deliver high capacity when hosting multivalent charge carriers, including Zn 2+ , Mn 2+ , Ni 2+ , and Al 3+ . 8,[19][20][21] The key challenge associated with the aqueous AIBs is the serious interactions between the Al 3+ charge carriers and solvent molecules and also host cathodes originating from the strong electrostatic eld around the bare Al 3+ ion. 22,23 Recently, energy researchers applied diverse materials engineering approaches to counter the electrostatic interactions associated with the multivalent charge carriers in the layered vanadiumbased cathodes.…”

“…18 In addition, the inbuilt characteristic multiple-oxidation-state feature of vanadium has been shown to deliver high capacity when hosting multivalent charge carriers, including Zn 2+ , Mn 2+ , Ni 2+ , and Al 3+ . 8,19–21…”