Revealing the key role of non-solvating diluents for fast-charging and low temperature Li-ion batteries

Fast-charging and low temperature operation are of vital importance for the further development of lithium-ion batteries(LIBs),which is hindered by the utilization of conventional carbonate-based electrolytes due to their slow kinetics,narrow operating temperature and voltage range.Herein,an acetonitrile(AN)-based localized high-concentration electrolyte(LHCE)is proposed to retain liquid state and high ionic conductivity at ultra-low temperatures while possessing high oxidation stability.We originally reveal the excellent thermal shielding effect of non-solvating diluent to prevent the aggregation of Li^(+) solvates as temperature drops,maintaining the merits of fast Li transport and facile desolvation as at room temperature,which bestows the graphite electrode with remarkable low temperature performance(264 mA h g^(-1) at-20 C).Remarkably,an extremely high capacity retention of 97%is achieved for high-voltage high-energy graphite||NCM batteries after 250 cycles at-20 C,and a high capacity of 110 mA h g^(-1)(71%of its room-temperature capacity)is retained at-30°C.The study unveils the key role of the non-solvating diluents and provides instructive guidance in designing electrolytes towards fast-charging and low temperature LIBs.

On Finite Non-Solvable Groups Whose Gruenberg-Kegel Graphs are Isomorphic to the Paw

The Gruenberg-Kegel graph(or the prime graph)Γ(G)of a finite group G is a graph,in which the vertex set is the set of all prime divisors of the order of G and two different vertices p and q are adjacent if and only if there exists an element of order pq in G.The paw is a graph on four vertices whose degrees are 1,2,2,3.We consider the problem of describing finite groups whose Gruenberg-Kegel graphs are isomorphic as abstract graphs to the paw.For example,the Gruenberg-Kegel graph of the alternating group A_(10)of degree 10 is isomorphic as abstract graph to the paw.In this paper,we describe finite non-solvable groups G whose Gruenberg-Kegel graphs are isomorphic as abstract graphs to the paw in the case when G has no elements of order 6 or the vertex of degree 1 ofΓ(G)divides the order of the solvable radical of G.

Classification about Non-Solvable Groups with Exactly 40 Maximal Order Elements

Let φ be a homomorphism from a group H to a group Aut（N）. Denote by Hφ× N the semidirect product of N by H with homomorphism φ. This paper proves that： Let G be a finite nonsolvable group. If G has exactly 40 maximal order elements, then G is isomorphic to one of the following groups： （1） Z4φ×A5, kerφ = Z2; （2） D8φ ×A5, kerφ = Z2 ×Z2; （3） G/N = S5, N = Z（G） = Z2; （4） G/N = S5, N = Z2 ×Z2, N∩Z（G） = Z2.

Non-solvating fluorosulfonyl carboxylate enables temperature-tolerant lithium metal batteries

Advanced electrolyte engineering is an important strategy for developing high-efficacy lithium(Li)metal batteries(LMBs).Unfortunately,the current electrolytes limit the scope for creating batteries that perform well over temperature ranges.Here,we present a new electrolyte design that uses fluorosulfonyl carboxylate as a non-solvating solvent to form difluoroxalate borate(DFOB-)anion-rich solvation sheath,to realize high-performance working of temperature-tolerant LMBs.With this optimized electrolyte,favorable SEI and CEI chemistries on Li metal anode and nickel-rich cathode are achieved,respectively,leading to fast Li^(+)transfer kinetics,dendrite-free Li deposition and suppressed electrolyte deterioration.Therefore,Li||LiNi_(0.80)Co_(0.15)Al_(0.05)O_(2)batteries with a thin Li foil(50μm)show a long-term cycling lifespan over 400 cycles at 1C and a superior capacity retention of 90%after 200 cycles at 0.5C under 25℃.Moreover,this electrolyte extends the operating temperature from-10 to 30℃and significantly improve the capacity retention and Coulombic efficiency of batteries are improved at high temperature(60℃).Fluorosulfonyl carboxylates thus have considerable potential for use in high-performance and allweather LMBs,which broadens the new exploring of electrolyte design.

INTERACTION BETWEEN ISOTACTIC POLYPROPYLENE AND ITS NON-SOLVENTS

Polypropylene (PP) microporous film prepared by biaxial stretching of isotactic PP is treated with non-solvent liquid at room temperature. The dimension of the him may change after the treatment. The degree of area contraction of PP film is dependent on the match between PP and liquid in solubility parameter and polarity, The fact indicates that some interactions do exist between liquid and isotactic PP, and a shrinkable porous him is a sensitive probe to detect the weak interactions.

STUDY ON SLOW-RELEASE CHARACTERISTICS OF MICROCAPSULES WITH EMULSION NON-SOLVENT ADDITION METHOD

An O / W emulsion non-solvent addition method was used to prepare ethyleellulose (EC) microcapsules of water soluble pharmaceutical (theophylline). The solvent and non-solvent reagents used in this work were toluene and cyclohexane. The effects of polymer concentration, core wall ratio and particle size on the kinetics as well as the dissolution rate of the drug were investigated. The results show that the dissolution rate increases with the increasing of polymer concentration and core wall ratio. The release of microcapsules prepared with different procedures can be selectively profiled with first order and Higuchi matrix kinetic models.

Rapid preparation of size-tunable nano-TATB by microfluidics

Nano-TATB was developed in microchannels by physical method and chemical method,respectively.The effects of total flow rate,number of microreactor plates,solvent/non-solvent ratio and temperature on the particle size of TATB in the physical method were studied.Prepared TATB were characterized by Nano Sizer,Scanning Electron Microscopy,Specific surface aperture analyzer,X-ray diffraction,Fourier transform infrared spectroscopy and Differential Scanning Calorimetry.The results show that the TATB obtained by physical method and chemical method are spherical,with average particle size of 130.66 nm and 108.51 nm,respectively.Specific surface areas of TATB obtained by physical and chemical methods are 21.37 m^(2)/g and 21.91 m^(2)/g,respectively.Compared with the specific surface area of micro-TATB(0.0808 m^(2)/g),the specific surface area of nano-TATB is significantly increased.DSC test results show that the smaller the particle size of TATB,the lower the thermal decomposition temperature.In addition,by simulating the mixing state of fluid in microchannels and combining with the classical nucleation theory,the mechanism of preparing nano-TATB by microchannels was proposed.

Fabrication of Dual-pore Scaffolds Using a Combination of Wire-Networked Molding （WNM） and Non-solvent Induced Phase Separation （NIPS） Techniques

In this study, to fabricate dual-pore scaffolds with interconnected pores, Non-solvent Induced Phase Separation （NIPS） and Wire-Network Molding （WNM） techniques were combined. First, a mold with uniform slits was prepared, and needles were inserted into the mold. Subsequently, polycaprolactone （PCL） pellets were dissolved in tetrahydrofuran （THF） at a specified ratio. The slurry was mixed using hot plate stirrer at 1200 rpm for 24 hours at 40 ~C. The PCL slurry was subsequently injected into the mold. Thereafter, to exchange the THF （solvent） with the ethanol （non-solvent）, the mold was soaked in an ethanol bath. After removing the mold from the ethanol bath, the needles were removed from the mold. Consequently, dual-pore scaffold with interconnected pores was obtained. The surface morphology of the fabricated scaffolds were observed using Scanning Electron Microscope （SEM）. Moreover, cell culture experiments were performed using the CCK-8 assay, and the characteristics of cells grown on the dual-pore scaffolds were assessed and were compared with the NIPS-based 3D plotting scaffold.

Preparation of Ultrafine TATB and the Technology for Crystal Morphology Control

The ultrafine 1,3,5-triamino-2,4,6-trinitrobenzene （TATB） has been prepared by using solvent and non-solvent method, and the influencing factors in close relationship with the grain size and crystal morphology control such as categories and dosage of surfactants, volume ratio of solvent to non-solvent have also been considered in this paper. It showed that these factors had remarkable effect on the crystal morphology, particle size and agglomeration during the crystallization process. By using 0.095% （mass percentage） ionic surfactant （S） as the additive and using spray-drops feeding device as the dropping equipment, 1.06 g TATB raw materials have been refined into free-running ellipsoid and spherical TATB grains with the grain size from 30 to 50 nm. By using 0.014% （mass percentage） non-ionic surfactant （P） as the additive, spherical TATB grains with the particle diameter of 50 nm and with narrow particle-size distribution have also been obtained. It was shown by the characterizations that the ultrafine particle of TATB had better heat resisting evenness and its 5 seconds ignition point is advanced by 7.5 K.

Poly(N,N-dimethylaminoethyl methacrylate) Grafted Poly(vinyl chloride)s Synthesized via ATRP Process and Their Membranes for Dye Separation

To functionalize poly（vinyl chloride）（PVC） for various applications, monomers containing tertiary amine group are incorporated into PVC via atom transfer radical polymerization（ATRP） initiated by the labile chlorines in their backbones. The kinetics of synthesis was carefully investigated, and it is proven that the grafting polymerization process can be effectively controlled by regulating the reaction time. The membranes are fabricated using PVC and copolymers by non-solvent induced phase separation（NIPS） process. The hydrophilicity and pore structure of copolymer membranes were enhanced as well, these membranes are endowed with positive charge. When PDMA%（i.e., the PDMA weight percentage in copolymer） is 31.1%, the flux and Victoria blue B rejection are 26.0 L·m·^-2·h^-1（0.5 MPa） and 91.2%, respectively. Thus, the newly synthesized polymer is proven to be a promising material for dye separation with positive charges.

Construction of Safety and Non-flammable Polyimide Separator Containing Carboxyl Groups for Advanced Fast Charing Lithium-ion Batteries

With the wide applications of lithium-ion batteries(LIBs)in electronic devices and electric vehicles,it is of great importance to improve their safety and electrochemical performance.Herein,soluble polyimides(PI)containing carboxyl groups(―COOH)were synthesized by a simple one-step method and PI separators with sponge-like,interpenetrating porous structures were prepared via non-solvent induced phase separation(NIPS).The obtained PI separators exhibited excellent thermal stability and fire-resistance properties,with the electrolyte uptake of 344%and good dimensional integrity in air at 200℃.The results showed that the lithium-ion transference number of the obtained PI separator could reach 0.48,which was much higher than that of the Celgard-2400 separator(0.38).The Li/LiFePO_(4) half-cell with the PI separator showed excellent cycle capability and high-rate performance with a high capacity of 121.80 mA·h·g^(-1) at 5 C,which was better than that of the cell with the Celgard-2400 separator(54.3 mA·h·g^(-1)),demonstrating the promising applications of this PI separators in LIBs.

Polydiacetylene-Tb3＋ Nanosheets of Which Both the Color and the Fluorescence Can Be Reversibly Switched between Two Colors

Polydiacetylenes （PDAs）, an organic layered compound, show a series of intriguing properties, such as thermo- chromism and fluorescence emission in the red-phase. However, their irreversible color change, and weak and sin- gle-color fluorescence emitted only from the red-phase PDAs, have limited their applications. Herein, we report double-reversible PDA-Tb3＋ nanosheets of which both the color and the fluorescence can be reversibly switched between two colors. PDA-Tb3＋ nanosheets have the nearly defect-free intercalated structure in which a layer of Tb3＋ ions was intercalated in between each two PDA bilayers to tether almost all of the carboxyl groups at the end of the side chains of the PDA. When the PDA is in the blue phase, the PDA-Tb3＋ nanosheets emit the green fluo- rescence of Tb3＋ ions. When the PDA is in the red phase, the Tb3＋ fluorescence disappears while the intrinsic red fluorescence of PDA is effectively enhanced through the fluorescence resonance energy transfer （FRET） process; the PDA-Tb3＋ nanosheets emit stronger red fluorescence compared with the PDA in red phase. Moreover, the teth- ering of almost all of the carboxyl groups at the end of the side chains of the PDA endows the nanosheets with the double reversibility in both the color and fluorescence transitions.

SYNTHESIS AND CHARACTERIZATION OF HIGH PERFORMANCE PA FILM

I. INTRODUCTIONIn last decade, considerable attention was focused on polyacetylene. However, its practical application was affected considerably because of its poor strength and stability. Recently, Narrmann et al. reported that they could synthesize PA film with improved properties using modified Ziegler-Natta catalyst. However, no