Architecting a Hydrated Ca_0.24V₂O₅ Cathode with a Facile Desolvation Interface for Superior-Performance Aqueous Zinc Ion Batteries

Abstract

Vanadium-based materials are promising cathode candidates for low-cost and high-safety aqueous zinc−ion batteries (AZIBs). However, they suffer from inferior rate capability and undesirable capacity fading due to their intrinsic poor conductivity and structural instability. Herein, we synthesize hydrated Ca 0.24 V 2 O 5 •0.75H 2 O (CaVOH) nanoribbons with in situ incorporations of the carbon nanotubes via a one-step hydrothermal method, achieving an integrated architecture hybrid cathode (C/ CaVOH) design. Benefitting from the robust structure and low desolvation interface, the prefabricated C/CaVOH cathodes deliver a high capacity of 384.2 mA h g −1 at 0.5 A g −1 with only 5.6% capacity decay over 300 cycles, enable an ultralong cycling life of 10,000 cycles at 20.0 A g −1 with 80.2% capacity retention, and exhibit an impressive rate capability (165 mA h g −1 at 40.0 A g −1 ) with a high mass loading of ∼4 mg cm −2 . Moreover, through the theoretical calculations and a series of ex situ characterizations, we demonstrate the Zn 2+ /H + co-intercalation storage mechanism, the key role of the gallery water, and the function of the induced C−O groups in promoting kinetics of the C/CaVOH electrode. This work highlights the strategy of in situ implanted high conductivity materials to engineer vanadium-based or other cathodes for highperformance AZIBs. KEYWORDS: aqueous Zn−ion battery, Ca 0.24 V 2 O 5 •0.75H 2 O nanoribbons, lower desolvation energy, Zn 2+ /H + hybrid storage mechanism, high reversibility

Calcium-intercalated birnessite MnO2 anchored on carbon nanotubes as high-performance cathodes for aqueous zinc-ion batteries

“…10,11 The lack of suitable cathode materials has greatly limited the practical application of ZIBs. 12 Various cathode materials have been developed to accommodate Zn 2+ , which mainly include Prussian blue analogs, 13,14 vanadium-based oxides, [15][16][17][18][19] and manganese-based oxides. [20][21][22][23] Manganese dioxides have become popular cathodes for aqueous Zn-ion batteries due to their low cost, non-toxicity, high theoretical specific capacity and high operation potential.…”

A Comprehensive Understanding of Interlayer Engineering in Layered Manganese and Vanadium Cathodes for Aqueous Zn‐Ion Batteries

“…Coincidentally, Huang et al [82] 8e. [83] The CaVOH cathode delivers ultralong cycling life, moreover, the role of a facile desolvation interface, co-preintercalated Ca 2 + /H 2 O, and CNTs was demonstrated by DFT calculations and a series of ex-situ characterizations. Besides, other Ca 2 + -pinned vanadium oxides as AZIBs cathode have also been developed.…”

“…Structural water could alleviate the desolvation enthalpy at the cathode/electrolyte interface by working as an “acceptor” to bear hydrated Zn 2+ after the desolvation process. It will screen the Coulombic repulsion at the interface as well [19d,83] Enhancing the Zn 2+ diffusion kinetics .…”

“…Studies uncovered that Ca 2+ as a structural stabilizer in CaVO undergoes fast, performance‐harmless ion exchange with Zn 2+ in the electrolyte, and the entire Zn 2+ ‐intercalation/deintercalation process is accompanied by counter migration of solvent water. Recently, our group, reported a hydrated Ca 0.24 V 2 O 5 ⋅ 0.75H 2 O (CaVOH) nanoribbons with in‐situ incorporation of carbon nanotubes, achieving an integrated architecture hybrid cathode (C/CaVOH) design, as illustrated in Figure 8e [83] . The CaVOH cathode delivers ultralong cycling life, moreover, the role of a facile desolvation interface, co‐pre‐intercalated Ca 2+ /H 2 O, and CNTs was demonstrated by DFT calculations and a series of ex‐situ characterizations.…”

Capacity-enhanced and kinetic-expedited zinc-ion storage ability in a Zn3V3O8/VO2cathode enabled by heterostructural design

“…22,23 Recently, some vanadate compounds (including Mg 2+ , Al 3+ , Ca 2+ and Zn 2+ ions) were exploited as new cathode materials that exhibited promising electrochemical properties. 24–28…”