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Aqueous rechargeable zinc-iodine batteries (ZIBs) are promising candidates for grid energy storage because they are safe and low-cost and have high energy density. However, the shuttling of highly soluble triiodide ions severely limits the device's Coulombic efficiency. Herein, we demonstrate for the first time a double-layered cathode configuration with a conductive layer (CL) coupled with an adsorptive layer (AL) for ZIBs. This unique cathode structure enables the formation and reduction of adsorbed I3- ions at the CL/AL interface, successfully suppressing triiodide ion shuttling. A prototypical ZIB using a carbon cloth as the CL and a polypyrrole layer as the AL simultaneously achieves outstanding Coulombic efficiency (up to 95.6%) and voltage efficiency (up to 91.3%) in the aqueous ZnI2 electrolyte even at high-rate intermittent charging/discharging, without the need of ion selective membranes. These findings provide new insights to the design and fabrication of ZIBs and other batteries based on conversion reactions.
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The voltage of carbon-based aqueous supercapacitors is limited by the water splitting reaction occurring in one electrode, generally resulting in the promising but unused potential range of the other electrode. Exploiting this unused potential range provides the possibility for further boosting their energy density. An efficient surface charge control strategy was developed to remarkably enhance the energy density of multiscale porous carbon (MSPC) based aqueous symmetric supercapacitors (SSCs) by controllably tuning the operating potential range of MSPC electrodes. The operating voltage of the SSCs with neutral electrolyte was significantly expanded from 1.4â V to 1.8â V after simple adjustment, enabling the energy density of the optimized SSCs reached twice as much as the original. Such a facile strategy was also demonstrated for the aqueous SSCs with acidic and alkaline electrolytes, and is believed to bring insight in the design of aqueous supercapacitors.
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To explore the mixing effect of litter decomposition and the role of detritivores, we conducted a laboratory-based microcosm experiment to study the influence of detritivores on litter mixture decomposition by using two litter species with contrasting quality, i.e., Cinnamomum camphora and Michelia × alba, and a detritivore (isopoda). After 100 days incubation, the decomposition rate of litter mixture was 52.1%, slower than that of M. alba (62.6%) and significantly faster than that of C. camphora (33.6%). The addition of isopods significantly increased litter decomposition rate, with C. camphora, M. alba, and the mixture increased by 14.4%, 20.1% and 22.1%, respectively. There was no significant mixing effect without isopods. Adding isopods significantly promoted the mixing effect of litter decomposition, with a value of the litter mixture decomposition effect of 8.6%. The detritivores increased litter decomposition rate and mixing effect through increasing consumption of litter with better quality.
Assuntos
Cinnamomum camphora , Ecossistema , Folhas de PlantaRESUMO
Aqueous rechargeable zinc-iodine batteries (ZIBs), including zinc-iodine redox flow batteries and static ZIBs, are promising candidates for future grid-scale electrochemical energy storage. They are safe with great theoretical capacity, high energy, and power density. Nevertheless, to make aqueous rechargeable ZIBs practically feasible, there are quite a few hurdles that need to be overcome, including self-discharge, sluggish kinetics, low energy density, and instability of Zn metal anodes. This article first reviews the electrochemistry in aqueous rechargeable ZIBs, including the flow and static battery configurations and their electrode reactions. Then the authors discuss the fundamental questions of ZIBs and highlight the key strategies and recent accomplishments in tackling the challenges. Last, they share their thoughts on the future research development in aqueous rechargeable ZIBs.
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Soil fungi are important components of belowground biodiversity and play important roles in soil carbon and nutrient cycling. We investigated fungal communities in the top soil (0-10 cm) of 22 Pinus massoniana forests in the Three Gorges Reservoir Region using high-throughput sequencing technique. We found that Ascomycota and Basidiomycota were the dominant fungi phyla, and Eurotiales, Russulales, and Tremellales were the most abundant fungi orders. The dominant functional groups in P. massoniana forests were saprophytic fungi, ectomycorrhizal fungi, and ericoid mycorrhizal fungi. Results of redundancy analysis showed that environmental variables but not spatial variables were the main drivers of soil fungal community structure across the 22 P. massoniana forests, which suggested that habitat filtering rather than dispersal limitation shaped soil fungal community structure. Aboveground biomass, soil conductivity, available phosphorus, soil bulk density, carbon to nitrogen ratio, nitrate concentration, and proportion of slit were the main factors explaining the variation in soil fungal community structure. It should be noted that the key factors influencing different fungal functional groups differed across forests.
Assuntos
Basidiomycota , Micobioma , Micorrizas , Pinus , Carbono , Florestas , Fungos , Nitratos , Nitrogênio , Fósforo , Solo/química , Microbiologia do SoloRESUMO
Aqueous rechargeable nickel-zinc batteries are highly attractive for large-scale energy storage for their high output voltage, low cost, and excellent safety; however, their inferior cycling durability due to the degradation of the Ni-based cathode is a major obstacle for their applications. In this context, we develop a new kind of porous electrochemically activated Ni nanoparticle/nitrogen-doped carbon (Ni/NC) composite material as ultrastable cathodes for advanced aqueous rechargeable nickel-zinc batteries. The in situ formation of a highly active NiO x(OH) y layer on Ni nanoparticles and a unique hydrophilic porous architecture endow the activated Ni/NC composite with high accessible area, abundant active sites, easy electrolyte permeation, and shortened charge/ion transport pathway. Consequently, a high capacity of 381.2 µAh cm-3 with an outstanding rate capability is achieved by the Ni-Zn battery using the optimized activated Ni/NC composite as the cathode (about 30-fold enhancement compared to that with the pristine Ni/NC composite as the cathode). More impressively, the as-assembled Ni-Zn battery achieves an unprecedented cyclic stability with no capacity loss after 36 000 charge/discharge cycles. This is the highest cyclic durability ever for Ni-Zn batteries and other aqueous rechargeable batteries. This novel efficient electrochemical activation strategy to achieve a high-performance cathode and demonstration of an ultrastable aqueous rechargeable Ni-Zn battery may open up new vistas on the development of more advanced and reliable energy storage materials and devices.
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A piezoelectric piezoelectric-metal-cavity (PMC) actuator was reported previously that can exhibit a large flexural displacement. In this paper, a lead-free piezoelectric ceramic was used as a driving element of the PMC actuator. Bi(0.5)(Na(0.725)K(0.175)Li(0.1))(0.5)TiO3 (abbreviated as BNKLT) is a soft-type piezoelectric ceramic with good piezoelectric properties at room temperature. Both the electrical and mechanical properties of the BNKLT PMC actuator were measured. With good piezoelectric coefficients and low density, the BNKLT ceramic has the potential to be used as the driving element of the lead-free actuator.