Vanadium-Based Cathodic Materials of Aqueous Zn-Ion Battery for Superior-Performance with Prolonged-Life Cycle

Aqueous Zn-ion battery systems (AZIBs) have emerged as the most dependable solution, as demonstrated by successful systematic growth over the past few years. Cost effectivity, high performance and power density with prolonged life cycle are some major reason of the recent progress in AZIBs. Development of vanadium-based cathodic materials for AZIBs has appeared widely. This review contains a brief display of the basic facts and history of AZIBs. An insight section on zinc storage mechanism ramifications is given. A detailed discussion is conducted on features of high-performance and long life-time cathodes. Such features include design, modifications, electrochemical and cyclic performance, along with stability and zinc storage pathway of vanadium based cathodes from 2018 to 2022. Finally, this review outlines obstacles and opportunities with encouragement for gathering a strong conviction for future advancement in vanadium-based cathodes for AZIBs.

Tremella-like Hydrated Vanadium Oxide Cathode with an Architectural Design Strategy toward Ultralong Lifespan Aqueous Zinc-Ion Batteries

Rechargeable aqueous zinc-ion batteries (ZIBs) are promising systems for energy storage due to their operational safety, low cost, and environmental friendliness. However, the development of suitable cathode materials is plagued by the sluggish dynamics of Zn²⁺ with strong electrostatic interaction. Herein, an Al³⁺-doped tremella-like layered Al_0.15V₂O₅·1.01H₂O (A-VOH) cathode material with a large pore diameter and high specific surface area is demonstrated to greatly boost electrochemical performance as ZIB cathodes. Resultant ZIBs with a 3 M Zn(CF₃SO₃)₂ electrolyte deliver a high specific discharge capacity of 510.5 mAh g^-1 (0.05 A g^-1), and an excellent energy storage performance is well maintained with a specific capacity of 144 mAh g^-1 (10 A g^-1) even after ultralong 10,000 cycles. The decent electrochemical performance roots in the novel tremella-like structure and the interlayer of Al³⁺ ions and water molecules, which could improve the electrochemical reaction kinetics and structural long cycle stability. Furthermore, the assembled coin-type cells could power a light-emitting diode (LED) lamp for 2 days. We believed that the design philosophy of unique morphology with abundant active sites for Zn²⁺ storage will boost the development of competitive cathodes for high-performance aqueous batteries.

A High-Voltage Zn-Organic Battery Using a Nonflammable Organic Electrolyte

Owing to undesired Zn corrosion and the formation of Zn dendrites in aqueous electrolytes, most of the examples of aqueous Zn batteries with reported excellent performance are achieved with low Zn-utilization (<0.6 %) in the anode and low mass-loading (<3 mg cm^-2 ) in the cathode. Herein, we propose a new organic electrolyte for Zn batteries, which contains a zinc trifluoromethanesulfonate (Zn-TFMS) salt and a mixed solvent consisting of propylene carbonate (PC) and triethyl phosphate (TEP). We demonstrate that this electrolyte with an optimized PC/TEP ratio not only exhibits high ionic conductivity and a wide stable potential window, but also facilitates dendrite-free Zn plating/stripping. In particular, the TEP solvent makes the electrolyte nonflammable. Finally, a 2 V Zn//polytriphenylamine composite (PTPAn) battery is fabricated with the optimized electrolyte; it shows a high rate and a long lifetime (2400 cycles) even with a high mass-loading (16 mg cm^-2 ) of PTPAn in the cathode and with a high Zn-utilization (3.5 %).