Engineering the Proton-Substituted HNaV₆O₁₆·4H₂O Cathode for the Ultrafast-Charging Zinc Storage

Abstract

The ultrafast charging property plays a significant role in achieving high-rate performance in a working aqueous battery system. However, the fast charging process usually causes irreversible structure evolution, thereby resulting into a dramatic capacity decay at high current densities. Herein, proton-substituted HNaV6O16·4H2O (HNVO) was fabricated via a facile hydrothermal method and utilized as the cathode of zinc ion batteries. The proton can not only serve as the interlayer pillar to stabilize the layer structure but also improve the utilization of active materials. In addition, the preinserted H+ is also beneficial for accelerating the kinetics of the charge carrier and reducing the electrochemical irreversibility, achieving a high-rate performance. In our case, the Zn/HNVO battery delivers 331.3 mA h g–1 (charged at 10.0 A g–1) and maintains 333.2 mA h g–1 (discharged at 1.0 A g–1) with a high Coulombic efficiency of 100.5%. Importantly, it also delivers an ultralong cycling stability with almost no capacity decay (10 000 cycles at 20 A g–1). This design of the cathode provides a new insight for developing ultrafast-charging aqueous battery systems.

Oxygen-Deficient HNaV6O16·4H2O@Reduced Graphene Oxide as a Cathode for Aqueous Rechargeable Zinc-Ion Batteries

“…Furthermore, we speculate that the insertion of protons and the presence of rGO induced V 5+ acquired electrons from O 2− and converted to V 4+ , while O 2− lost electrons to form oxygen molecules, leaving the system to form oxygen vacancies. 53 Figure 1E,F shows the SEM image of the O d -HNaVO@rGO sample, in which banded HNaVO samples with 100 nm width and 500−1000 nm length are randomly mixed with layered rGO to form O d -HNaVO@rGO composite samples, which is also confirmed by the TEM diagram in Figure S1e. Meanwhile, EDS characterization is adopted to investigate the elemental distribution on the surface of O d -HNaVO@rGO composite samples, as shown in Figure S2, which also confirms the uniform composite of rGO and HNaVO samples.…”

“…Simultaneously, the clear signals of electrons trapped in oxygen vacancies in HNaVO and O d -HNaVO@rGO samples are observed at the paramagnetic center g factor of 2.0080 and 2.0100, respectively, revealing that there exist oxygen vacancies in HNaVO and O d -HNaVO@rGO samples, , and the oxygen vacancy signal of the O d -HNaVO@rGO sample is stronger, which is consistent with the XPS fine spectrum analysis results of Figure B,C and Figure S1d. Furthermore, we speculate that the insertion of protons and the presence of rGO induced V 5+ acquired electrons from O 2– and converted to V 4+ , while O 2– lost electrons to form oxygen molecules, leaving the system to form oxygen vacancies …”

Proton‐Induced Defect‐Rich Vanadium Oxides as Reversible Polysulfide Conversion Sites for High‐Performance Lithium Sulfur Batteries

“…Then, 15 mL NaCl (2 mol L −1 ) solution was added into the above dispersions dropwise under continuous stirring for 96 h at room temperature. The as‐obtained mixture was washed with deionized water to remove impurities and the NVO was obtained after freeze‐drying process [52] . Subsequently, NVO was dissolved in deionized water to form a uniform dispersion, then the GO (5 mg mL −1 ) solution was added drop by drop to the above solution and continuously stirred for 4 h, and finally 3 mL of H 2 O 2 was added and stirred for 20 min.…”

“…The as-obtained mixture was washed with deionized water to remove impurities and the NVO was obtained after freezedrying process. [52] Subsequently, NVO was dissolved in deionized water to form a uniform dispersion, then the GO (5 mg mL À 1 ) solution was added drop by drop to the above solution and continuously stirred for 4 h, and finally 3 mL of H 2 O 2 was added and stirred for 20 min. The obtained mixture was transferred into a 50 mL Teflon-lined stainless steel autoclave and heated at 140 °C for 5 h. The G@HNVO nanobelts with 0, 10, 20, and 30 % GO (mass percentages) were prepared by washing and freeze-drying approach (Figure S1).…”

High-performance Zn-ion batteries constructed byin situconversion of surface-oxidized vanadium nitride into Zn3(OH)2V2O7·2H2O with oxygen defects

“…1,2 Aqueous zinc ion batteries (AZIBs) have been a recent research hotspot because of their low cost, environmental friendliness, and excellent safety of aqueous electrolytes, which can make up for the shortcomings of lithium-ion batteries. [3][4][5] Cathode materials have a critical effect on the electrochemical properties of AZIBs. Therefore, a variety of materials have been explored to serve as cathodes for AZIBs, including manganese-based oxides, 5,6 vanadium-based oxides, [7][8][9] Prussian blue analogs, 10,11 and so on.…”