In Situ Induced Core–Shell Carbon‐Encapsulated Amorphous Vanadium Oxide for Ultra‐Long Cycle Life Aqueous Zinc‐Ion Batteries

Abstract

Inevitable dissolution in aqueous electrolytes, intrinsically low electrical conductivity, and sluggish reaction kinetics have significantly hampered the zinc storage performance of vanadium oxide‐based cathode materials. Herein, core–shell N‐doped carbon‐encapsulated amorphous vanadium oxide arrays, prepared via a one‐step nitridation process followed by in situ electrochemical induction, as a highly stable and efficient cathode material for aqueous zinc‐ion batteries (AZIBs) are reported. In this design, the amorphous vanadium oxide core provides unobstructed ions diffusion routes and abundant active sites, while the N‐doped carbon shell can ensure efficient electron transfer and greatly stabilize the vanadium oxide core. The assembled AZIBs exhibit remarkable discharge capacity (0.92 mAh cm−2 at 0.5 mA cm−2), superior rate capability (0.51 mAh cm−2 at 20 mA cm−2), and ultra‐long cycling stability (≈100% capacity retention after 500 cycles at 0.5 mA cm−2 and 97% capacity retention after 10 000 cycles at 20 mA cm−2). The working mechanism is further validated by in situ X‐ray diffraction combined with ex situ tests. Moreover, the fabricated cathode is highly flexible, and the assembled quasi‐solid‐state AZIBs present stable electrochemical performance under large deformations. This work offers insights into the development of high‐performance amorphous vanadium oxide‐based cathodes for AZIBs.

Tuning [VO6] Octahedron of Ammonium Vanadates via F Incorporation for High‐Performance Aqueous Zinc Ion Batteries

“…The relationship between peak current (i) and scan rate (v) is denoted as: i = a𝜈 b , where both a and b are constants. [51,52] The b value reflects the kinetic information of the electrochemical process, in which b = 0.5 is regarded as the diffusion-controlled behavior, while b = 1.0 indicates a dominant pseudocapacitive process. [53] As shown in the Figure 4b, there is a fitted linear relationship be-tween log(i) and log(v) with slopes of 0.56, 1.06, 0.75, and 0.44 for peaks 1, 2, 3, and 4, respectively, indicating the presence of both diffusion-controlled and pseudocapacitive behavior in the F-NVO electrode.…”

Mitigating cathodic dissolution through interfacial water masking to enhance the longevity of aqueous zinc–ion batteries

“…4,5 Unfortunately, these cathodes grapple with a significant challenge: pronounced dissolution in aqueous solutions, which is prone to lead to capacity decline. 6,7 This issue is highly related to the desolvation process of the hydrated [Zn(H 2 O) x ] 2+ ion at the cathode-electrolyte interface, [8][9][10] where a significant amount of active bound water is released. Different from the free water in the solvent, bound water often exhibits higher polarity and reactivity.…”

Interface engineering of amorphous/crystalline heterojunctions with synergistic Ru doping for efficient hydrazine oxidation assisted overall water splitting

“…26,27 Particularly, when amorphous VO x acts as the active site, it can not only regulate the adsorption and desorption of intermediates but also provide more ion diffusion paths and vacancies, thus improving the catalyst activity and stability. 28,29 Therefore, constructing a heterogeneous structure utilizing the three ingredients mentioned above could be a viable approach to obtaining catalysts that possess both high activity and stability by virtue of synergistic effects.…”