Mechanistic Insights of Zn²⁺ Storage in Sodium Vanadates

Abstract

Rechargeable aqueous zinc‐ion batteries (ZIBs) with high safety and low‐cost are highly desirable for grid‐scale energy storage, yet the energy storage mechanisms in the current cathode materials are still complicated and unclear. Hence, several sodium vanadates with NaV3O8‐type layered structure (e.g., Na5V12O32 and HNaV6O16·4H2O) and β‐Na0.33V2O5‐type tunneled structure (e.g., Na0.76V6O15) are constructed and the storage/release behaviors of Zn2+ ions are deeply investigated in these two typical structures. It should be mentioned that the 2D layered Na5V12O32 and HNaV6O16·4H2O with more effective path for Zn2+ diffusion exhibit higher ion diffusion coefficients than that of tunneled Na0.76V6O15. As a result, Na5V12O32 delivers higher capacity than that of Na0.76V6O15, and a long‐term cyclic performance up to 2000 cycles at 4.0 A g−1 in spite of its capacity fading. This work provides a new perspective of Zn2+ storage mechanism in aqueous ZIB systems.

Pseudo‐Zn–Air and Zn‐Ion Intercalation Dual Mechanisms to Realize High‐Areal Capacitance and Long‐Life Energy Storage in Aqueous Zn Battery

“…Tongye Wei, Qian Li, Gongzheng Yang,* and Chengxin Wang* DOI: 10.1002/aenm.201901480 intrinsically safe and low cost. [3,4] In terms of structure, Zn batteries can be classified into two types. [5] One is the closed system, such as Zn-Ni, Zn-Mn, and Zn-ion batteries (ZIBs) using weak acidic or mild electrolytes.…”

Novel Insights into Energy Storage Mechanism of Aqueous Rechargeable Zn/MnO2 Batteries with Participation of Mn2+

“…Aqueous rechargeable zinc-ion batteries (ZIBs) are developed as a battery system, in which low-cost, non-toxic, and naturally abundant zinc metal is used as an anode and environment-friendly neutral aqueous Zn 2+ -containing solution serves as electrolyte [8]. In recent years, a series of high-performance cathode materials for ZIBs have also been studied such as Prussian blue analog [9][10][11], vanadium oxides [12][13][14][15][16][17][18][19], manganese oxides [20][21][22][23][24][25][26][27][28], and some metal sulfides [29][30][31]. Among these materials, MnO 2 is particularly concerned for its high theoretical specific capacity, low cost, eco-friendliness, and diverse crystallographic polymorphs (e.g., α-MnO 2 , δ-MnO 2 , and γ-MnO 2 ) [27,28,32].…”

Highly Reversible Phase Transition Endows V6O13 with Enhanced Performance as Aqueous Zinc‐Ion Battery Cathode

“…[17][18][19][20][21][22] Nevertheless, it is worthy to note that the research of aqueous ZIBs is still in its infancy, and something is still unclear and debatable with regard to their Zn 2þ storage mechanism. For instance, the dominated Zn 2þ insertion/extraction process has been universally illustrated in some vanadium oxides and vanadates, [6,[11][12][13][23][24][25][26][27][28][29] while Niu and co-workers demonstrated the simultaneous Zn 2þ and H þ insertion in the aqueous Zn/NaV 3 O 8 ·H 2 O batteries. [15] On the basis of the aqueous Zn/MnO 2 system, Kang and co-workers identified the insertion type of MnO 2 cathode, [17] while a chemical conversion reaction was detected by Liu and co-workers [19] The Zn 2þ storage/release behavior of aqueous ZIBs is critical for their electrochemical behavior; thus, it is significant to execute scientific and systematic research to explore the advanced storage mechanism targeting outstanding performance.…”