3D Hierarchically Structured CoS Nanosheets: Li+ Storage Mechanism and Application of the High-Performance Lithium-Ion Capacitors.

Lithium-ion capacitors possess excellent power and energy densities, and they can combine both of those advantages from supercapacitors and lithium-ion batteries, leading to novel generation hybrid devices for storing energy. This study synthesized one three-dimensional (3D) hierarchical structure, self-assembled from CoS nanosheets, according to a simple and efficient manner, and can be used as an anode for lithium ion capacitors. This CoS anode, based on a conversion-type Li+ storage mechanism dominated by diffusion control, showed a large reversible capacity, together with excellent stability for cycling. The CoS shows a discharge capacity ≈434 mA h/g at 0.1 A/g. The hybrid lithium-ion capacitor, which had the CoS anode as well as the biochar cathode, exhibits excellent electrochemical performance with ultrahigh energy and power densities of 125.2 Wh/kg and 6400 W/kg, respectively, and an extended cycling life of 81.75% retention after 40 000 cycles. The CoS with self-assembled 3D hierarchical structure in combination with a carbon cathode offers a versatile device for future applications in energy storage.

A facile strategy for the synthesis of three-dimensional heterostructure self-assembled MoSe2 nanosheets and their application as an anode for high-energy lithium-ion hybrid capacitors.

As energy storage devices, lithium-ion hybrid capacitors (LIHCs) are currently favored by researchers, because they combine the high energy density of lithium-ion batteries and the high power density as well as the long cycle life of electric double-layer capacitors. However, the reason that LIHCs are problematic for researchers and cannot be applied practically is the slow dynamic behavior of the battery type anode that leads to low magnification and cycle performance of the anode, furthermore, causing a dynamic imbalance between the Faraday embedded electrode and the capacitive electrode. Hence, it is imperative to find an anode material that can quickly intercalate/de-intercalate lithium. In this study, a novel anode material, MoSe2 nanoflowers, for LIHCs was incorporated through a facile solvothermal technique. The MoSe2 nanoflowers with a small volume change after Li+ insertion, conducive to a rapid kinetic layered heterostructure, result in extraordinary electrochemical performance. The prepared MoSe2 nanoflowers exhibit very good invertible capacity (641.4 mA h g-1 at 0.1 A g-1 after 200 cycles), superior velocity performance (380.3 mA h g-1 at 5 A g-1) and long-term cycling stability (214.6 mA h g-1 even after 1000 cycles at 1 A g-1) as anode materials for LIHCs. Benefiting from the reasonable nanometer size effect, locally fine charge transfers and low energy diffusion barriers, MoSe2 nanoflowers possess high rate pseudocapacitive behavior. In addition, the assembled MoSe2//AC (AC, activated carbon) LIHCs deliver a high energy density (78.75-39.1 W h kg-1) and high-power characteristic (150-3600 W kg-1). Besides, after 5000 cycles, the capacity retention rate is 70.28% under a broad potential window (0.5-3.5 V). This LIHC based on a transition metal selenide as an anode shows great potential for application in the fields of new energy electric vehicles and smart electronic products.

Complete genome sequence and genomic characterization of Microcystis panniformis FACHB 1757 by third-generation sequencing.

The cyanobacterial genus Microcystis is well known as the main group that forms harmful blooms in water. A strain of Microcystis, M. panniformis FACHB1757, was isolated from Meiliang Bay of Lake Taihu in August 2011. The whole genome was sequenced using PacBio RS II sequencer with 48-fold coverage. The complete genome sequence with no gaps contained a 5,686,839 bp chromosome and a 38,683 bp plasmid, which coded for 6,519 and 49 proteins, respectively. Comparison with strains of M. aeruginosa and some other water bloom-forming cyanobacterial species revealed large-scale structure rearrangement and length variation at the genome level along with 36 genomic islands annotated genome-wide, which demonstrates high plasticity of the M. panniformis FACHB1757 genome and reveals that Microcystis has a flexible genome evolution.