Lithium conducting ionic liquids based on lithium borate salts

The simple reaction of trialkoxyborates with butyllithium resulted in the obtaining of new lithium borate salts: Li{[CH₃(OCH₂CH₂)_nO]₃BC₄H₉}, containing oxyethylene substituents (EO) of n = 1, 2, 3 and 7. Salts of n ≥ 2 show properties of room temperature ionic liquid (RTIL) of low glass transition temperature, T_g of the order from −70 to −80 °C. The ionic conductivity of the salts depends on the number of EO units, the highest conductivity is shown by the salt with n = 3; in bulk its ambient temperature conductivity is 2 × 10⁻⁵ S cm⁻¹ and in solution in cyclic propylene sulfite or EC/PC mixture, conductivity increases by an order of magnitude. Solid polymer electrolytes with borate salts over a wide concentration range, from 10 to 90 mol.% were obtained and characterized. Three types of polymeric matrices: poly(ethylene oxide) (PEO), poly(trimethylene carbonate) (PTMC) and two copolymers of acrylonitrile and butyl acrylate p(AN-BuA) were used in them as polymer matrices. It has been found that for systems of low salt concentration (10 mol.%) the best conducting properties were shown by solid polymer electrolytes with PEO, whereas for systems of high salt concentration, of the polymer-in-salt type, good results were achieved for PTMC as polymer matrix.     

Investigation and application of lithium difluoro(oxalate)borate (LiDFOB) as additive to improve the thermal stability of electrolyte for lithium-ion batteries

Lithium difluoro (oxalate) borate (LiDFOB) is used as thermal stabilizing and solid electrolyte interface (SEI) formation additive for lithium-ion battery. The enhancements of electrolyte thermal stability and the SEIs on graphite anode and LiFePO₄ cathode with LiDFOB addition are investigated via a combination of electrochemical methods, nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared-attenuated total reflectance (FTIR-ATR), as well as density functional theory (DFT). It is found that cells with electrolyte containing 5% LiDFOB have better capacity retention than cells without LiDFOB. This improved performance is ascribed to the assistance of LiDFOB in forming better SEIs on anode and cathode and also the enhancement of the thermal stability of the electrolyte. LiDFOB-decomposition products are identified experimentally on the surface of the anode and cathode and supported by theoretical calculations.     

Electrochemical characterization of electrolytes for lithium-ion batteries based on lithium difluoromono(oxalato)borate

The salt lithium difluoromono(oxalato)borate (LiDFOB) showed some promising results for lithium-ion-cells. It was synthesized via a new synthetic route that avoids chloride impurities. Here we report the properties of its solutions (solvent blend ethylene carbonate/diethyl carbonate (3:7, mass ratio), including its conductivity, cationic transference number, hydrolysis, Al-current collector corrosion-protection ability and its cycling performance with some electrode materials. Some Al-corrosion studies were also performed with the help of our recently developed computer controlled impedance scanning electrochemical quartz crystal microbalance (EQCM) that proofed to be a useful tool for battery material investigations.     

Electrochemical stability of lithium bis(oxatlato) borate containing solid polymer electrolyte for lithium ion batteries

The electrochemical stability of lithium bis(oxatlato) borate (LiBOB) containing solid polymer electrolyte has been evaluated both by inert electrode and real cathodes. Enhanced intrinsic anodic stability and decreased interface impedance, are obtained by addition of nano-sized MgO to PEO₂₀-LiBOB. It is also found that the LiBOB-containing SPEs exhibit prominent kinetic stability between 3.0 and 4.5 V. For cells using SPEs as the separators, good cycling performance is obtained for real 4 V class cathodes material LiNi_1/3Co_1/3Mn_1/3O₂ and LiCoO₂. The Li|PEO₂₀-LiBOB|LiNi_1/3Co_1/3Mn_1/3O₂ cell takes an initial capacity of 156.8 mAh g⁻¹, with retention of 142.5 mAh g⁻¹ after 20 cycles at 0.2C-rate. The cell also works well up to 1C-rate. The addition of nano-sized MgO into PEO₂₀-LiBOB readily reduces the irreversible capacity per cycle, both for LiNi_1/3Co_1/3Mn_1/3O₂ and LiCoO₂ cathodes. In addition, the critical role of LiBOB in obtaining kinetic stability and passivating ability towards cathodes are specially discussed.     

Conductivity,thermal behavior and microstructure of new composites based on AgI–Ag2O–B2O3 glasses with Al2O3 matrix

A series of Ag⁺-ion conducting composites consisting of glasses of the AgI–Ag₂O–B₂O₃ system and hard Al₂O₃ powder matrix were synthesized by a high-pressure route (pressure 7.7 GPa, temperature 100–200 °C). The composition of the glasses was described by the general formula: xAgI·(100 − x)(0.667Ag₂O·0.333B₂O₃), where x = 40, 50 and 60. Alumina powder (2 μm average grain size) was added to the glass in 50/50 proportions (by volume).     

Synthesis of a quaternary ammonium derivative of chito‐oligosaccharide as antimicrobial agent for cellulosic fibers

A derivative of chito‐oligosaccharide (COS), N‐(2‐hydroxyl)propyl‐3‐trimethyl ammonium chito‐oligosaccharide chloride (HTACC), was synthesized using a reaction of glycidyltrimethylammonium chloride (GTMAC) and COS prepared by depolymerization of a fully deacetylated chitosan. COS and HTACC were applied to the cotton fabrics with a pad‐dry‐cure process using the reaction between the hydroxyl group of cellulose and terminal aldehyde group in COS and HTACC. Their minimum inhibition concentration (MIC) was evaluated, and the antimicrobial activity and durability to laundering of cotton fabrics treated with them were compared. The complete substitution of NH₂ groups in COS with GTMAC was obtained at a 4 : 1 mol ratio of GTMAC to NH₂ in 18 h at 80°C under the presence of acetic acid. MIC values of the 1.04 DS of HTACC and COS were 50 and 400 μg/mL, respectively. A cotton fabric treated with 0.2% of HTACC and 1.8% of COS exhibited 100% reduction of bacteria. At the 50th laundering cycle, 0.3% of HTACC and 2.4% of COS indicated 100% bacterial reduction. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 2009–2015, 2000     

Studies of inverse emulsion copolymerization of (2-methacryloyloxyethyl) trimethyl ammonium chloride and acrylamide

Inverse emulsion copolymerization of (2-methacryloyloxyethyl) trimethyl ammonium chloride with acrylamide initiated with potassium persulfate has been studied dilatometrically. Aqueous monomer solutions were emulsified in kerosene with a blend of two surfactants (Span80 and OP10). The gel effect is evident from the increase of the molecular weight with conversion and also from the percentage of conversion versus time curves. Monomer reactivity ratios have been derived as r_AM = 0.38 and r_DMC = 1.69 at pH 6.8. The effects of initiator concentration, concentration, and composition of the monomer, emulsifier concentration, etc., on the polymerization rate and intrinsic viscosity of polymer have been examined. The rate of polymerization (R_p) can be represented by R_p I^0.52[M]^1.50[E]^0.38. The overall activation energy for the rate of polymerization is 66.0 kJ mol (40–65°C). Based on these experimental results, some aspects of the polymerization mechanism are discussed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1005–1010, 1998     

Large‐scale anaerobic degradation of betaine

Betaine, also known as N,N,N‐trimethyl glycine, is a soluble nitrogenous compound present at significant concentrations in sugar‐beet molasses. Molasses is used as substrate in a wide range of industrial fermentations, for example, alcohol, acid and yeast cell production. Betaine is not consumed to any significant extent during these fermentations and appears to largely pass through the subsequent processing stages, becoming an important constituent of the wastewater produced by these industries. The present study confirmed that betaine is present in large amounts in sugar‐beet molasses (up to 6% w/w) and in the effluent of processes using sugar‐beet molasses as substrate (up to 4.5 g dm⁻³). Betaine appeared to be almost completely degraded in the two full‐scale anaerobic treatment plants sampled. This was confirmed by anaerobic activity tests performed with both acclimated and unacclimated anaerobic sludge. The results obtained suggest the possible involvement of a multistep degradation process, with the likelihood of a nitrogen‐containing intermediate. Finally, although not totally discountable, betaine degradation does not appear to be coupled to sulfate reduction during treatment of high‐sulfate wastewaters. © 1999 Society of Chemical Industry     

分光光度法测定阳离子表面活性剂在砂岩表面的吸附

为测定阳离子表面活性剂十六烷基三甲基氯化铵(1631)在岩石表面的吸附量,利用紫外分光光度法,检测了1631溶液在岩石表面吸附前后的质量浓度,算出1631在岩石表面的吸附量。结果表明,用紫外分光光度法检测阳离子表面活性剂浓度快速准确,确定617nm为测定波长,线性回归方程为y=0 0027x-0 0058,R2=0 9991;不同砂岩表面的吸附平衡时间不同,亲水表面为10h,油表面为16h,砂表面为18h;同砂岩表面的静态饱和吸附量不同,亲水表面是0 7mg·g-1·砂,亲油表面是1 4mg·g-1·砂,油砂表面是6 7mg·g-1·砂;天然岩心动态吸附量为0 8066mg·g-1·砂。