Triple‐Functional Polyoxovanadate Cluster in Regulating Cathode, Anode, and Electrolyte for Tough Aqueous Zinc‐Ion Battery

Abstract

due to its intrinsic thermodynamics instability. [4][5][6][7][8] The dissolution issue of cathode material (manganese-based oxides, vanadium-based compounds, polyoxometalate [POM] clusters, etc.) directly causes severe performance deterioration in aqueous batteries. [5,[9][10][11] Especially, high-nuclearity POMs with reversible multielectron redox chemistry have demonstrated some promise as Zn 2+ host in AZIBs, but still suffer from severe capacity fading due to their water-soluble feature. [7,11,12] A stable cathode electrolyte interface (CEI) is generally useful in stabilizing the conventional cathodes in aqueous electrolytes. [10,13] Zhou et al. demonstrated a CEI layer of CaSO 4 •2H 2 O formed on the surface of Ca 2 MnO 4 to effectively suppress material dissolution via an electrochemically charging process. [4] Yet the developmental CEI for POM-based cathodes is still absent to date. To broaden the feasibility of POM-based electrodes in AZIBs, it should be charming and economical if a protective CEI can be constructed in situ to stabilize the POM-based cathodes.Besides the cathode dissolution, other fatal issues, including an unstable electrolyte environment due to the parasitic H 2 O ionization and metallic Zn anode stemming from uncontrollable dendrite formation, have hindered the development of AZIBs. [3,14,15] Various Zn anode stabilization strategies, including building Zn anode protective layers, [16] regulating Despite a promising outlook due to the intrinsic low cost and high safety, the practical application of aqueous Zn-ion battery is impeded by the severe mutual problems of cathode dissolution, electrolyte parasitic reactions, and metallic anode dendrite growth. Herein, a triple-functional strategy is proposed that a polyoxovanadate (POV) cluster of K 10 [V IV 16 V V 18 O 82 ] as a promising Zn 2+ host can concomitantly stabilize the cluster cathode, aqueous electrolyte, and metallic Zn anode. An in situ generated cathode electrolyte interface via anodic oxidation is identified as effective in preventing the dissolution of POV cathode. Molecular dynamics simulation and density functional theory calculation confirm that the [V IV 16 V V 18 O 82 ] 10− polyoxoanions can synergistically suppress electrolyte side reactions by modulating the primary solvation shell of Zn 2+ -6H 2 O, and random anode dendrite growth by in situ constructing a stable solid electrolyte interface of Zn-POV. As a result, the Zn//POV battery exhibits unprecedented cycling durability over 10 000 cycles at high rates of 5 and 12 A g −1 . In a systematic consideration, the findings enlighten the origin of triple-functional polyoxometalates and will significantly propel the practical development of aqueous batteries.

Multifunctional Electrolyte Additive Enables Highly Reversible Anodes and Enhanced Stable Cathodes for Aqueous Zinc-Ion Batteries

“…As zinc metal is a dense hexagonal lattice crystal at room temperature, zinc microcrystals tend to form solid sheet-like dendrite structures during electrochemical deposition. These undesirable dendrites not only consume the Zn anode, which reduces the reversibility and efficiency of the anode, but also penetrate the separator that causes a short circuit inside the battery and then damages the entire battery. , Various strategies have been proposed in the past few years to solve this problem, including designing anode structure, construction of zinc-friendly SEI protective layers, development of anode-free materials, and electrolyte optimization strategies, , and so forth. These strategies have made good progress in inhibiting dendrite growth on the surface of the Zn metal anode.…”

Lanthanide-Anderson Polyoxometalates Frameworks: Efficient Sulfide Photooxidation

“…Polyoxometalates (POMs) are anionic metal-oxide clusters with diverse nuclearities, modifiable oxygen-rich surfaces, and accessible organic grafting. , They have strong thermal stability, high negative charges, and remarkable redox abilities. These POM derivatives have been widely applied in areas ranging from electrochemistry to photochromism, medicine, and magnetism, − particularly exhibiting excellent catalytic performance due to their satisfying Lewis acidity and charge accumulation capability. , The incorporation of POMs into well-defined architectures produced another level of complexity with interesting behavior, not only the unique structure and functional features of POMs could be passed to the target materials, but also synergetic effects between POMs and a well-defined framework derive specific function-driven architectures. Metal–organic frameworks (MOFs) are porous frameworks with designable topology and functionalities, and they are widely applied in the fields of gas adsorption and separation, catalysis, and sensors. − In contrast to conventional porous materials, the modulation of metal nodes of MOFs has great influence on both structural aesthetics and functional extension. − Lanthanide (Ln) ions possess high coordination number, abundant coordination configuration, and robust Lewis acidity, enabling Ln-MOFs with special capability in numerous catalytic systems …”

Three photochromic materials based on POMs and viologens for UV probing, visual detection of metal ions and amine detection

“…1,2 Their enormous diversity in composition and structure allows them to exhibit good oxidation/reduction and photo-activity and excellent stability, which can be used in many fields such as electrochemistry, magnetism, materials science, catalysis, medicine and photochemistry. 3–13 The negative charge on the surface of a polyoxometalate is stable and its solubility is good. The ability of POMs to reversibly accept and release electrons through valence bond changes in the metal center is one of their most important properties and POMs can be widely used in photochromic materials.…”