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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]

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]

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]

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]

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]

In this paper, a series of novel Na 2 SiF 6 :Mn 4+ ,Li + (NSF:0.05Mn4+, x Li+) phosphors were prepared with the cation exchange method. Some novel luminescent properties inducing by doping Li+ were observed: First, the striking thing is that the excitation (PLE) & emission (PL) intensities of Li+-doped sample (NSF:0.05Mn4+, 0.08Li+) are 11.7 times higher than those of NSF:0.05Mn4+; Second, when the concentration of Li+≥ 20%: (a) transition of 4A 2g →4T 2g in excitation band and zero phonon line (ZPL), s- v 4 in emission band are all split into two peaks, respectively; (b) the peak intensities of as- v 6 , ZPL, v 6 and v 4 in emission band are almost the same. The mechanism of these phenomena was discussed. The color purity, crystal-field, nephelauxetic effect, the critical distance and the multipolar interaction for the samples were determined. Besides, the optimal sample (NSF:0.05Mn4+, 0.08Li+) has an excellent QY, which is as high as 99.83%. Good warm white light with low correlated color temperature (CCT = 4362 K) and high color rendering index (Ra = 88.5) was obtained from prototype WLEDs using the mixing phosphors of the optimal sample and YAG:Ce3+ on InGaN chip under a 20 mA drive current, making the optimal sample has potential application for blue light-based warm WLEDs. Image 1 • Na 2 SiF 6 : y Mn4+, x Li+ were synthesized with cation exchange method. • Intensity of PL was enhanced 11.7 times by doping Li+. • PLE and PL bands have novel obvious splitting peaks. • When x ≥ 20%, intensities of as- v 6 , ZPL, v 6 and v 4 are almost the same. [ABSTRACT FROM AUTHOR]

Abstract A series of Na 2 TiF 6 : x Mn4+ samples were prepared by the cation exchange method. Visible QC behavior and the strongest ZPL peaks were observed for these samples. The characteristic of the visible QC behavior is that PL intensity at 620 nm is 1.61 times as high as PLE intensity at 476 nm. The mechanisms of these phenomena were discussed, and the color purity, crystal-field and nephelauxetic effect, the critical distance and the multipolar interaction for the samples were determined. The result shows that the Mn4+ ions are located at a strong crystal field and the concentration quenching of Mn4+ is from the quadrupole-quadrupole interaction. The slightly increase of nephelauxetic ratio causes the slightly blue shift of emission. The color-purity and chromaticity coordinates of the optimal sample suggests that the strongest ZPL makes its red emission with high color-purity. Thus, Na 2 TiF 6 :0.08Mn4+ is a potential red-emitting phosphor for blue light-based WLEDs. [ABSTRACT FROM AUTHOR]

[Display omitted] • NH 4 + storage properties of VO x @PPy are studied for the first time. • Synergistic interaction between VO x and PPy enhances the performance of the composite electrode. • The NH 4 +/H+ co-insertion mechanism is proposed. • VO x @PPy exhibits a high capacity of 195 mAh/g. Aqueous ammonium-ion batteries (AAIBs) are attracting attention, mainly due to the unique interaction between NH 4 + and the host materials. Yet, few studies focus on the development of high-performance anode materials for NH 4 + storage, hindering the applications of AAIBs. Herein, we study the electrochemical NH 4 + storage properties of an electrodeposited vanadium oxide/polypyrrole (VO x @PPy) electrode with a core–shell structure. The strong interaction between PPy and VO x enhances the electrochemical performance of the composite electrode. The electrons in N atoms from PPy are attracted by V cations from VO x , resulting in the enhanced protonation level of PPy and the reduction of V in the composite material. Therefore, VO x @PPy exhibits a high specific capacity of 195.36 mAh/g at 0.2 A/g in ammonium acetate electrolyte, outperforming other reported anode materials for NH 4 + storage. In addition, the conformal PPy coating can efficiently suppress VO x dissolution, leading to good cycling stability for VO x @PPy. We assembled an aqueous ammonium-ion battery using VO x @PPy as the anode. The device exhibits a good energy density of 74.1 Wh kg−1 at the power density of 75.6 W kg−1. This work highlights the advantages of the hybrid organic/inorganic materials for NH 4 + storage and could push the development of aqueous ammonium-ion batteries. [ABSTRACT FROM AUTHOR]

Soil conservation ecosystem services (SCESs) are related to food production, safety of residents, water quality, and public health. However, the traditional assessment framework only focuses on a single dimension of SCESs, and the efficiency and development trends are often overlooked. A multidimensional assessment framework was established to assess SCESs in terms of the total output, efficiency, development trend temporally and spatially. Additionally, the traditional perspective of influencing mechanism analysis was expanded to include spatial heterogeneity. The influencing strength and distance were quantitatively revealed at pixel resolution. The results indicate that (1) the SCESs in Minnesota were generally improved from 1998 to 2018. (2) 70% and 78% of the counties experienced low-output and low-efficiency problems, respectively. (3) The Twin Cities constituted the degradation cores of SCESs in Minnesota. (4) The cropland and forestland proportions and rainfall were the top three influencing factors, causing SCES changes of 0.9959%, 0.4937%, and 0.1536%, respectively, for every 1% change in these factors. (5) According to the influence scopes, the soil organic carbon (SOC) content, normalized difference vegetation index (NDVI), and soil silt content were classified as long-distance factors, the soil sand content, slope and soil clay content were categorized as moderate-distance factors, and the remaining variables were identified as short-distance factors. (6) The influencing factors imposed both positive and negative influences on the SCESs, and attenuation or alteration of the adverse influences on SCESs through specific human interventions is a very promising approach. • A multidimensional assessment framework was proposed. • The SCESs in Minnesota has been severe with an upward development. • Degradations were classified into five types at county level and concentrated at "Twin Cities". • The proportions of cropland, forestland, and rainfall were the strongest influencing strength factors. • The influencing factors are classified as long-distance, moderate-distance, and short-distance factors. [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]