No abstract

Rechargeable aqueous zinc ion batteries (ZIBs) are highly desirable for large-scale energy storage due to their advantages of safety and low-cost. Development of advanced cathodes for use in aqueous ZIBs is urgently needed. Herein, we report a low-cost rechargeable aqueous Zn-V2O5 cell with 3 M ZnSO4 electrolyte that demonstrates high zinc storage capability. We also investigated the effect of different types/concentrations of the aqueous electrolytes on the performance of the Zn-V2O5 cells.

Rechargeable aqueous zinc‐ion batteries (ZIBs) with high safety and low‐cost are highly desirable for grid‐scale energy storage, yet the energy storage mechanisms in the current cathode materials are still complicated and unclear. Hence, several sodium vanadates with NaV3O8‐type layered structure (e.g., Na5V12O32 and HNaV6O16·4H2O) and β‐Na0.33V2O5‐type tunneled structure (e.g., Na0.76V6O15) are constructed and the storage/release behaviors of Zn2+ ions are deeply investigated in these two typical structures. It should be mentioned that the 2D layered Na5V12O32 and HNaV6O16·4H2O with more effective path for Zn2+ diffusion exhibit higher ion diffusion coefficients than that of tunneled Na0.76V6O15. As a result, Na5V12O32 delivers higher capacity than that of Na0.76V6O15, and a long‐term cyclic performance up to 2000 cycles at 4.0 A g−1 in spite of its capacity fading. This work provides a new perspective of Zn2+ storage mechanism in aqueous ZIB systems.

Background Mangroves are ecologically and economically important forests of the tropics. As one of the most carbon-rich biomes, mangroves account for 11% of the total input of terrestrial carbon into oceans. Although viruses are considered to significantly influence local and global biogeochemical cycles, little information is available regarding the community structure, genetic diversity and ecological roles of viruses in mangrove ecosystems. Methods Here, we utilised viral metagenomics sequencing and virome-specific bioinformatics tools to study viral communities in six mangrove soil samples collected from different mangrove habitats in Southern China. Results Mangrove soil viruses were found to be largely uncharacterised. Phylogenetic analyses of the major viral groups demonstrated extensive diversity and previously unknown viral clades and suggested that global mangrove viral communities possibly comprise evolutionarily close genotypes. Comparative analysis of viral genotypes revealed that mangrove soil viromes are mainly affected by marine waters, with less influence coming from freshwaters. Notably, we identified abundant auxiliary carbohydrate-active enzyme (CAZyme) genes from mangrove viruses, most of which participate in biolysis of complex polysaccharides, which are abundant in mangrove soils and organism debris. Host prediction results showed that viral CAZyme genes are diverse and probably widespread in mangrove soil phages infecting diverse bacteria of different phyla. Conclusions Our results showed that mangrove viruses are diverse and probably directly manipulate carbon cycling by participating in biomass recycling of complex polysaccharides, providing the knowledge essential in revealing the ecological roles of viruses in mangrove ecosystems. Electronic supplementary material The online version of this article (10.1186/s40168-019-0675-9) contains supplementary material, which is available to authorized users.