Application of PVDF Organic Particles Coating on Polyethylene Separator for Lithium Ion Batteries.

Surface coating modification on a polyethylene separator serves as a promising way to meet the high requirements of thermal dimensional stability and excellent electrolyte wettability for lithium ion batteries (LIBs). In this paper, we report a new type of surface modified separator by coating polyvinylidene fluoride (PVDF) organic particles on traditional microporous polyethylene (PE) separators. The PE separator coated by PVDF particles (PE-PVDF separator) has higher porosity (61.4%), better electrolyte wettability (the contact angle to water was 3.28° ± 0.21°) and superior ionic conductivity (1.53 mS/cm) compared with the bare PE separator (51.2%, 111.3° ± 0.12°, 0.55 mS/cm). On one hand, the PVDF organic polymer has excellent organic electrolyte compatibility. On the other hand, the PVDF particles contain sub-micro spheres, of which the separator can possess a large specific surface area to absorb additional electrolyte. As a result, LIBs assembled using the PE-PVDF separator showed better electrochemical performances. For example, the button cell using a PE-PVDF as the separator had a higher capacity retention rate (70.01% capacity retention after 200 cycles at 0.5 C) than the bare PE separator (62.5% capacity retention after 200 cycles at 0.5 C). Moreover, the rate capability of LIBs was greatly improved as well-especially at larger current densities such as 2 C and 5 C.

Waste to Wealth: Exhausted Nitrogen-Doped Mesoporous Carbon/MgO Desulfurizers Turned to High-Sulfur-Loading Composite Cathodes for Li-S Batteries.

We demonstrate a sustainable and cost-effective route to fabricate high-sulfur-loading cathode materials with the cooperative interfaces of "sulfiphilic" and "lithiophilic" sites from the removal industry of the pollutant H2S gas. The MgO-impregnated and nitrogen-doped mesoporous carbon composite desulfurizers (NMC/MgO), acting as effective catalysts and large storehouses, could catalytically oxidize H2S into elemental S with high catalytic selectivity and sulfur capacity. The obtained byproduct NMC/MgO/S-CO composites possess high sulfur loading (73.8 wt %) and significant structure advantages for practical application in Li-S batteries. First, the uniform distribution of S in the NMC/MgO frameworks via the in situ catalytic oxidation approach could offer large interface area for charge transport and Li+ reaction. Then, the cooperative effects of the "sulfiphilic" MgO nanoparticles and the "lithiophilic" nitrogen dopants in the NMC/MgO could effectively suppress the polysulfide shuttling. Under the further assistance of physical confinement of the mesoporous NMC/MgO, the NMC/MgO/S-CO composites present excellent electrochemical performances with a high reversible capacity of 772 mAh g-1 and a Coulombic efficiency of 93.6% at the 100th cycle at 0.2 C. These encouraging results not only develop a sustainable way to turn waste into wealth but also provide a promising strategy to product high-sulfur-loading cathode materials with uniform distribution of S through the in situ catalytic strategy for high-performance Li-S batteries.

In situ reactive coating of metallic and selenophilic Ag2Se on Se/C cathode materials for high performance Li-Se batteries.

A facile methodology to fabricate a metallic and selenophilic Ag2Se coating on a Se/nitrogen-doped mesoporous carbon composite, has been successfully developed based on the in situ redox reaction between Se and AgNO3 under ambient conditions. The in situ reactive growth of Ag2Se on Se ensures the complete encapsulation of Se by the Ag2Se coating, which endows the Ag2Se coating with the dual effects of physical entrapment and chemical binding to effectively confine polyselenide intermediates within the cathodes. With the further assistance of mesopore confinement of the nitrogen-doped carbons, the Ag2Se-coated Se/nitrogen-doped mesoporous carbon composites present much improved electrochemical performances with a high initial discharge capacity of 652 mA h g-1, a high coulombic efficiency of 95.4% and a high reversible capacity of 382 mA h g-1 after 100 cycles. These encouraging results suggest that the in situ reactive construction of metallic and chalcogenophilic coating layers on the chalcogen (e.g. S, Se and Te)-based electrode materials should be a promising and easy to scale-up method for practical applications of lithium batteries in light of the very simple in situ reaction processes involved.

Heteroatomic SenS8-n Molecules Confined in Nitrogen-Doped Mesoporous Carbons as Reversible Cathode Materials for High-Performance Lithium Batteries.

A reversible cathode material in an ether-based electrolyte for high-energy lithium batteries was successfully fabricated by homogeneously confining heteroatomic SenS8-n molecules into nitrogen-doped mesoporous carbons (NMCs) via a facile melt-impregnation route. The resultant SenS8-n/NMC composites exhibit highly reversible electrochemical behavior, where selenium sulfides are recovered through the reversible conversion of polysulfoselenide intermediates during discharge-charge cycles. The recovery of selenium sulfide molecules endows the SenS8-n/NMC cathodes with the rational integration of S and Se cathodes. Density functional theory calculations further reveal that heteroatomic selenium sulfide molecules with higher polarizability could bind more strongly with NMCs than homoatomic sulfur molecules, which provides more efficient suppression of the shuttling phenomenon. Therefore, with further assistance of mesopore confinement of the nitrogen-doped carbons, the Se2S6/NMC composite with an optimal Se/S mole ratio of 2/6 presents excellent cycle stability with a high initial Coulombic efficiency of 96.5% and a high reversible capacity of 883 mAh g(-1) after 100 cycles and 780 mAh g(-1) after 200 cycles at 250 mA g(-1). These encouraging results suggest that the heteroatomization of chalcogen (such as S, Se, or Te) molecules in mesostructured carbon hosts is a promising strategy in enhancing the electrochemical performances of chalcogen/carbon-based cathodes for Li batteries.

Dual-responsive polypseudorotaxanes based on block-selected inclusion between polyethylene-block-poly(ethylene glycol) diblock copolymers and 1,4-diethoxypillar[5]arene.

Based on the selective recognition of the polyethylene (PE) block of polyethylene-block-poly(ethylene glycol) (PE-b-PEG) by 1,4-diethoxypillar[5]arene (DEP5A), two novel thermo and competitive guest (1,4-dibromobutane or hexanedinitrile) responsive polypseudorotaxanes (PPRs) have been successfully constructed. The formation of PPRs both in solution and in the solid state was demonstrated by (1)H NMR, 2D NOESY, and WAXD analyses. TGA data illustrate that PPRs exhibit higher thermal stability than their precursor diblock copolymers. Moreover, intriguing porous disk-like aggregates are produced by electrospraying of PPRs in CHCl3 and the self-assembled structures of PPRs are totally changed by the addition of 1,4-dibromobutane or hexanedinitrile, demonstrating their competitive guest stimuli-responsiveness.

Melamine-assisted one-pot synthesis of hierarchical nitrogen-doped carbon@MoS2 nanowalled core-shell microspheres and their enhanced Li-storage performances.

A facile and scalable one-pot approach has been developed to synthesize carbon@MoS2 core-shell microspheres by a hydrothermal method, which involves the fast formation of melamine-resorcinol-formaldehyde polymeric microspheres in situ, followed by direct growth of the MoS2 nanowalls on them. The results give unequivocal proof that melamine could be the key to forming the core-shell microspherical morphology, and the contents of MoS2 shells can be easily tuned by initial ratios of the precursors. After a simple heat treatment, the obtained carbon@MoS2 microspheres simultaneously integrate the nitrogen-doped carbon cores and the hierarchical shells which consist of few-layered MoS2 nanowalls with an expanded interlayer spacing. Their unique architectures are favourable for high electronic/ionic conductivity and accommodate volume strain during the electrochemical reaction of the MoS2 anodes in lithium-ion batteries. Thus, a very high reversibility capacity of 771 mA h g(-1) at 100 mA g(-1) after 100 cycles, and a rate capacity of 598 mA h g(-1) at 2000 mA g(-1) could be achieved for the carbon@MoS2 core-shell microspheres with the optimal composition. Furthermore, a thin carbon coating on the carbon@MoS2 microspheres could further increase the reversible capacity to 856 mA h g(-1) after 100 cycles at 100 mA g(-1). These encouraging results suggest that such a facile and efficient protocol can provide a new pathway to produce hierarchical core-shell microspheres which integrate the structural, morphological and compositional design rationales for advanced lithium-ion batteries.

Bottom-up catalytic approach towards nitrogen-enriched mesoporous carbons/sulfur composites for superior Li-S cathodes.

We demonstrate a sustainable and efficient approach to produce high performance sulfur/carbon composite cathodes via a bottom-up catalytic approach. The selective oxidation of H2S by a nitrogen-enriched mesoporous carbon catalyst can produce elemental sulfur as a by-product which in-situ deposit onto the carbon framework. Due to the metal-free catalytic characteristic and high catalytic selectivity, the resulting sulfur/carbon composites have almost no impurities that thus can be used as cathode materials with compromising battery performance. The layer-by-layer sulfur deposition allows atomic sulfur binding strongly with carbon framework, providing efficient immobilization of sulfur. The nitrogen atoms doped on the carbon framework can increase the surface interactions with polysulfides, leading to the improvement in the trapping of polysulfides. Thus, the composites exhibit a reversible capacity of 939 mAh g(-1) after 100 cycles at 0.2 C and an excellent rate capability of 527 mAh g(-1) at 5 C after 70 cycles.

High efficiency immobilization of sulfur on nitrogen-enriched mesoporous carbons for Li-S batteries.

Nitrogen-enriched mesoporous carbons with tunable nitrogen content and similar mesoporous structures have been prepared by a facile colloid silica nanocasting to house sulfur for lithium-sulfur batteries. The results give unequivocal proof that nitrogen doping could assist mesoporous carbon to suppress the shuttling phenomenon, possibly via an enhanced surface interaction between the basic nitrogen functionalities and polysulfide species. However, nitrogen doping only within an appropriate level can improve the electronic conductivity of the carbon matrix. Thus, the dependence of total electrochemical performance on the nitrogen content is nonmonotone. At an optimal nitrogen content of 8.1 wt %, the carbon/sulfur composites deliver a highest reversible discharge capacity of 758 mA h g(-1) at a 0.2 C rate and 620 mA h g(-1) at a 1 C rate after 100 cycles. Furthermore, with the assistance of PPy/PEG hybrid coating, the composites could further increase the reversible capacity to 891 mA h g(-1) after 100 cycles. These encouraging results suggest nitrogen doping and surface coating of the carbon hosts are good strategies to improve the performance carbon/sulfur-based cathodes for lithium-sulfur batteries.

Short-term curative effect of electroacupuncture as an adjunctive treatment on schizophrenia / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To compare the short-term curative effect of clozapine (CZ) and its combination with electroacupuncture (EA) in treating schizophrenia.</p><p><b>METHODS</b>Ninety schizophrenia patients were randomly divided into two groups equally: the EA group treated with combination of CZ (200 - 300 mg/d in mean) and EA, and the CZ group treated with CZ alone. The effects of treatment were evaluated with PANSS, CGI and TESS before and at the 2th, 4th, 6th and 8th weekend of the treatment.</p><p><b>RESULTS</b>The initiation of effect in the two groups was the same, the total effective rate was 75% in the EA group and 73% in the CZ group. However, somatic complaint was lower and compliance was higher in the EA group than that in the CZ group respectively.</p><p><b>CONCLUSION</b>With the effect equal to CZ, combination of CZ and EA shows higher compliance in treating schizophrenia, which would be beneficial in the later stage treatment for consolidation.</p>