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Aqueous batteries with high safety and cost efficiency usually employ metallic cations as charge carriers. Recently, ammonium (NH4+) ion batteries using the nonmetal NH4+ as a charge carrier exhibit distinct electrochemical features from conventional aqueous batteries. Herein, the electrochemical performances of a bimetallic hydroxide material are systematically studied with different charge carriers in the electrolytes, including NH4+, as well as the conventional monovalent metallic cations K+ and Na+, respectively. Electrochemical results indicate that the charge storage process using NH4+ as the working ions exhibits a higher discharge plateau, smaller electrochemical polarization, and larger discharge capacity than that using conventional metallic charge carriers. Experimental characterizations and theoretical calculations suggest that the strong interaction between NH4+ and the electrode material, as well as the low NH4+‐ion diffusion barrier lead to these superior electrochemical features. The assembled NH4+‐ion battery exhibits a good energy density of 123 Wh kg(cathode+anode)−1 at the power density of 480 W kg(cathode+anode)−1. These fundamental findings are important for developing good safety, low‐cost, and high‐energy aqueous batteries with sustainable NH4+ charge carriers. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous Zn‐VOx batteries are attracting attention in large scale energy storage applications. Yet, the sluggish Zn2+ diffusion kinetics and ambiguous structure–property relationship are always challenging to fulfil the great potential of the batteries. Here we electrodeposit vanadium oxide nanobelts (VO‐E) with highly disordered structure. The electrode achieves high capacities (e.g. ≈5 mAh cm−2, 516 mAh g−1), good rate and cycling performances. Detailed structure analysis indicates VO‐E is composed of integrated amorphous‐crystalline nanoscale domains, forming an efficient heterointerface network in the bulk electrode, which accounts for the good electrochemical properties. Theoretical calculations indicate that the amorphous‐crystalline heterostructure exhibits the favorable cation adsorption and lower ion diffusion energy barriers compared to the amorphous and crystalline counterparts, thus accelerating charge carrier mobility and electrochemical activity of the electrode. [ABSTRACT FROM AUTHOR]

The limited choice of anode materials always challenges the development of high performance aqueous ammonium-ion batteries (AAIBs). Herein, we fabricate amorphous molybdenum oxide (MoOx) materials and study the NH4+ storage performances. The results indicate that the optimized electrode exhibits high gravimetric/areal capacities of 175 mA h g−1/1.30 mA h cm−2, outperforming state-of-the-art anode materials for AAIBs. Our findings indicate that the valence state of Mo and the Mo–O–H content in MoOx synergistically control the NH4+ storage performances, offering new understanding for rational design of MoOx materials for energy storage applications. [ABSTRACT FROM AUTHOR]

Transition metal layered double hydroxides (LDHs) are widely used as high‐performance cathode materials for aqueous alkaline zinc (Zn) batteries. Yet, the strongly alkaline electrolytes may lead to undesirable rechargeability of the alkaline devices and environmental issues. Herein, as a research prototype, CoNi LDH material is designed with abundant H vacancies using electrochemical methods (denoted as CoNi LDH(v)). As a Zn‐ion battery cathode, CoNi LDH(v) exhibits promising electrochemical performances in mild ZnSO4 electrolyte, such as a good specific capacity of 185 mAh g−1 at the current density of 1.2 A g−1, a high average discharge potential of 1.6 V versus Zn2+/Zn, and a large energy density of 296.2 Wh kg−1 at the power density of 1894 W kg−1, outperforming most of the cathode materials for aqueous Zn‐ion batteries. Experimental and computational results indicate that the introduced H vacancies in the double hydroxide matrix induce the improved electronic conductivity and cation adsorption thermodynamics, endowing the double hydroxides with good electrochemical activity for reversible cation insertion. Structural and spectroscopy studies identify that CoNi LDH(v) experiences reversible H+/Zn2+ co‐intercalation mechanism in an aqueous ZnSO4 electrolyte. As far as it is known, it is the first report on transition‐metal‐based double hydroxides used for mild aqueous Zn‐ion batteries. [ABSTRACT FROM AUTHOR]

Manganese (Mn) oxides are promising cathode materials for rechargeable aqueous Zn‐ion batteries. However, the Mn dissolution in weakly acidic electrolytes always hinders the development of better aqueous Zn–Mn batteries. Herein, a hydroxylated manganese oxide cathode material (H‐MnO2) is fabricated using an electrochemical method for stable aqueous Zn–Mn batteries without relying on the Mn2+ electrolyte additives. The partial hydroxylation of the oxides leads to charge redistribution of the material, changing the reaction thermodynamics and kinetics. Theoretical simulation suggests that the hydroxylation of manganese oxide promotes both Zn2+ adsorption thermodynamics and diffusion kinetics on the surface of H‐MnO2 but weakens the interaction between H+ and the electrode. Therefore, Zn2+ ions can be more reactive with the hydroxylated manganese oxide than H+ ions. Experimental results show that the Zn2+ insertion mechanism dominates the charge storage process of H‐MnO2, and the H+‐induced Mn dissolution reaction is effectively alleviated. Importantly, H‐MnO2 exhibits good cycling stability with 95% capacity retention over 5000 cycles at the current density of 3.8 A g−1 in the ZnSO4 electrolyte, outperforming the state‐of‐the‐art aqueous Zn–Mn batteries, even those with Mn2+ electrolyte additives. The findings provide new insights for designing stable manganese oxide cathodes in aqueous Zn–Mn batteries. [ABSTRACT FROM AUTHOR]

Red light purity of red emitting phosphor is an important factor for using in warm white light-emitting diodes (WLEDs). In order to obtain red emitting phosphor with good red light purity, a series of Na2TiF6:0.08Mn4+, xLi+ samples were prepared with the cation exchange method. Phenomena of zero phonon line as the strongest peak and strong enhancement induced by Li+ were observed. The mechanisms of the phenomena are discussed and proposed. From the result of temperature-dependent behavior measurement and stability test, it can be known that the optimal sample exhibited good thermal stability and color stability under WLEDs working conditions. Finally, prototype WLEDs was fabricated with the optimal sample and Y3Al5O12:Ce3+ (YAG:Ce3+) based on InGaN chip. Warm white light with low correlated color temperature (CCT = 4393 K) and high color rendering index (Ra = 90.5 and R9 = 89) was obtained, making it had potential application for blue light-based warm WLEDs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reversible MnO 2 /Mn2+ transformation is realized in mild aqueous electrolytes. • The Zn-Mn hybrid battery exhibit high discharge capacity and long cycle life. • The disproportionation of Mn3+ triggers the Mn2+ dissolution. • H+/Zn2+ insertion and the disproportionation occur sequentially upon discharging. The disproportionation of the Jahn-Teller (J-T) active manganese oxides (Mn3+) often leads to uncontrollable Mn2+ dissolution, which has been identified as one of the major causes of the performance degradation in conventional Zn-MnO 2 batteries. Herein, we use the "unwanted" disproportionation of the Mn3+ cations to realize effective MnO 2 /Mn2+ transformation, achieving high specific capacity (550 mAh g−1) and good cycling stability (5000 cycles without capacity decay) in a Zn-MnO 2 hybrid battery with mild aqueous electrolytes. Mechanism study shows that MnO 2 is deposited on the cathode during charging, H+/Zn2+ insertion and disproportionation occur sequentially during discharging, leading to Mn2+ dissolution. The generated high-valence manganese oxides via disproportionation further experience reduction-disproportionation-dissolution, which proceeds repeatedly in the expanded discharge potential to 0 V vs. Zn2+/Zn, resulting in the complete dissolution of the cathodic materials. Our results provide the fundamental understanding on the controversial mechanisms of Zn-MnO 2 batteries with mild aqueous electrolytes and highlight the effect of disproportionation in pushing the electrochemical performance of the promising Zn-MnO 2 hybrid batteries. [ABSTRACT FROM AUTHOR]

There has been a growing interest in developing catalysts to enable the reversible iodine conversion reaction for high-performance aqueous zinc-iodine batteries (AZIBs). While diatomic catalysts (DACs) have demonstrated superior performance in various catalytic reactions due to their ability to facilitate synergistic charge interactions, their application in AZIBs remains unexplored. Herein, we present, for the first time, a DAC comprising Mn-Zn dual atoms anchored on a nitrogen-doped carbon matrix (MnZn-NC) for iodine loading, resulting in a high-performance AZIB with a capacity of 224 mAh g-1 at 1 A g-1 and remarkable cycling stability over 320,000 cycles. The electron hopping along the Mn-N-Zn bridge is stimulated via a spin exchange mechanism. This process broadens the Mn 3dxy band width and enhances the metallic character of the catalyst, thus facilitating charge transfer between the catalysts and reaction intermediates. Additionally, the increased electron occupancy within the d-orbital of Zn elevates Zn's d-band center, thereby enhancing chemical interactions between MnZn-NC and I-based species. Furthermore, our mechanism demonstrates potential applicability to other Metal-Zn-NC DACs with spin-polarized atoms. Our work elucidates a clear mechanistic understanding of diatomic catalysts and provides new insights into catalyst design for AZIBs., (© 2024 Wiley‐VCH GmbH.)

The development of aqueous ammonium-ion batteries (AAIBs) is currently attracting great attention because of the interesting electrochemical features induced by the charge carrier NH 4 + . One possible way to improve the performance of AAIBs is increasing the salt concentration in the electrolyte. Yet, few studies focus on the complex electrode-electrolyte interface behaviors in highly concentrated electrolytes, which affect the electrochemical performance of AAIBs significantly. Herein, we aim to understand the impact of CH 3 COONH 4 electrolyte concentration on the NH 4 + storage performance of a bimetallic hydroxide material. Experimental and theoretical simulation results indicate that the acetate anion will participate in the construction of the solvated NH 4 + in a highly concentrated electrolyte, facilitating the adsorption of the solvated NH 4 + cluster on the electrode surface. Besides, a new partial de-solvation model is also proposed, demonstrating an energy favorable de-solvation process. Finally, an ammonium-ion hybrid battery is designed, which provides a high average discharge voltage of 1.7 V and good energy density of 368 W h kg (cathode) -1 , outperforming most of the state-of-the-art aqueous batteries. This work provides new understanding about the electrode's interfacial chemistry in different concentrated CH 3 COONH 4 electrolytes, establishes a correlation between the electrolyte concentration and the electrode's performances, and demonstrates the superiority of the hybrid ammonium-ion battery design., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Rechargeable aqueous Zn-VO x batteries are attracting attention in large scale energy storage applications. Yet, the sluggish Zn 2+ diffusion kinetics and ambiguous structure-property relationship are always challenging to fulfil the great potential of the batteries. Here we electrodeposit vanadium oxide nanobelts (VO-E) with highly disordered structure. The electrode achieves high capacities (e.g., ≈5 mAh cm -2 , 516 mAh g -1 ), good rate and cycling performances. Detailed structure analysis indicates VO-E is composed of integrated amorphous-crystalline nanoscale domains, forming an efficient heterointerface network in the bulk electrode, which accounts for the good electrochemical properties. Theoretical calculations indicate that the amorphous-crystalline heterostructure exhibits the favorable cation adsorption and lower ion diffusion energy barriers compared to the amorphous and crystalline counterparts, thus accelerating charge carrier mobility and electrochemical activity of the electrode., (© 2023 Wiley-VCH GmbH.)

The limited choice of anode materials always challenges the development of high performance aqueous ammonium-ion batteries (AAIBs). Herein, we fabricate amorphous molybdenum oxide (MoO x ) materials and study the NH 4 + storage performances. The results indicate that the optimized electrode exhibits high gravimetric/areal capacities of 175 mA h g -1 /1.30 mA h cm -2 , outperforming state-of-the-art anode materials for AAIBs. Our findings indicate that the valence state of Mo and the Mo-O-H content in MoO x synergistically control the NH 4 + storage performances, offering new understanding for rational design of MoO x materials for energy storage applications.