Hydrated Intercalation for High‐Performance Aqueous Zinc Ion Batteries

Abstract

as smartphones, electric vehicles, and energy storage systems depend on LIBs to provide the necessary power for optimal performance. Today, that dependency continues to grow at an exponential rate as the portfolio of electronic devices and vehicles diversifies. The common denominator for the myriad of commercialized devices is the constant demand for high power and long usage time. Accordingly, the frontrunners of today's technology are striving to optimize LIBs to meet such performance demands. While such efforts have extended the usage time of various devices, this direction has also exposed critical issues with current battery technology: safety and cost.The main cause for safety hazards with LIBs is linked to the use of organic electrolytes. In the unfortunate event of a short circuit in a battery, a sudden burst of exothermic reactions is accelerated by the presence of organic solvents, which act as fuel for ensuing fires. This problem is exacerbated in high energy density configurations where materials are densely packed. The risk of fire hazards has prompted a search for alternative battery systems, among which rechargeable aqueous batteries have garnered significant attention as viable candidates for safe batteries. Replacing the organic solvent with water as the electrolyte medium has significant implications. In addition to the benefit of heightened safety, water has a high ionic conductivity compared to conventional organic solvents (2-3 orders of magnitude higher), a useful quality for high C-rate operations. Moreover, the use of water can reduce costs incurred from moisture regulation during manufacturing.Unfortunately, despite these attractive aspects, aqueous electrolytes impose certain barriers. Most critically, the thermodynamic stability window of water is limited to 1.23 V, beyond which detrimental hydrogen and oxygen evolution reactions (HER/OER) occur. As a result, even if kinetic overpotentials are taken into account, the operating potential windows of aqueous batteries are significantly narrower than those of their organic counterparts. This motivates the search for adequate materials that provide maximum energy within such a narrow voltage window. The prevalent layered oxide/graphite system used in conventional LIBs is no longer an option in this system due to such voltage constraints. Instead, on the anode side, zinc (Zn) metal is considered to be a promising candidate. [1] Not only is Zn abundant in nature, nontoxic, and cheap, but its metallic Aqueous zinc ion batteries (AZIBs) are steadily gaining attention based on their attractive merits regarding cost and safety. However, there are many obstacles to overcome, especially in terms of finding suitable cathode materials and elucidating their reaction mechanisms. Here, a mixed-valence vanadium oxide, V 6 O 13 , that functions as a stable cathode material in mildly acidic aqueous electrolytes is reported. Paired with a zinc metal anode, this material exhibits performance metrics of 360 mAh g −1 at 0.2 A g −1 , 92% capacity retention after...

Unlocking the Potential of Disordered Rocksalts for Aqueous Zinc‐Ion Batteries

“…The local chemical and electronic environment of the disordered rocksalt was further characterized by X‐ray absorption spectroscopy (XAS). As shown in Figure c and Figure S21 (Supporting Information), after charging to 1.8 V, the absorption edge is shifted toward a higher energy, implying a higher oxidation state of vanadium . And the valences of V are mainly between V 4+ and V 5+ , which is well consistent with the above formula VN x O y ( x ≈ 0.2, y ≈ 2.1) obtained from XPS, aberration‐corrected TEM, ICP‐OES, and elemental analysis.…”

Multi‐Scale Investigations of δ‐Ni0.25V2O5·nH2O Cathode Materials in Aqueous Zinc‐Ion Batteries

“…Similar phenomenon can be also observed in previous reports on vanadium‐based cathodes. [ 53–55 ] Therefore, the nearly irreversible insertion/extraction reaction and negligible contribution to capacity from proton intercalation indicate that the Zn 2+ intercalation mechanism mainly dominate in as‐prepared cathode material and it will be further confirmed by the following multiple ex situ characterizations. Combined ex situ X‐ray photoelectron spectroscopy (XPS), XRD and TEM analyses were carried out to investigate the possible Zn 2+ insertion/extraction in the Ni 0.25 V 2 O 5 ·nH 2 O electrode.…”

Intercalation Pseudocapacitive Zn2+ Storage with Hydrated Vanadium Dioxide toward Ultrahigh Rate Performance

“…The curves were highly coincident in subsequent cycles, and both the reduction and oxidation peaks hardly changed during the subsequent cycles, revealing that the redox reaction of HVO was highly reversible. [28] In addition, the broad peaks symbolize the capacitance-like characteristic during the Zn-ion de(intercalation) process. initial discharge capacity of 280 mAh g −1 was achieved, then the capacity reached 318 mAh g −1 for the second cycle and maintained high retention ratio of 98% after 200 cycles (Figure 2c).…”