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Effect of linear carboxylic ester on low temperature performance of LiMn_2O_4-graphite cells

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Transactions of Nonferrous Metals Society of China 2015年第1期25卷 206-210页

作者：洪树李劼王冠超张治安赖延清中南大学冶金与环境学院长沙410083

To improve the low-temperature performances of Li-ion cells, three types of linear carboxylic ester-based electrolyte, such as EC/EMC/EA（1：1：2, mass ratio）, EC/EMC/EP（1：1：2, mass ratio） and EC/EMC/EB（1：1：2, mass ratio）, were prepared to substitute for industrial electrolyte（EC/EMC/DMC）. Then, 18650-type Li Mn2O4-graphite cells（nominal capacity of 1150 mA ·h） were assembled and studied. Results show that the cells containing three types of electrolyte are able to undertake 5C discharging current with above 93% capacity retention at-20 °C. Electrochemical impedance spectra show that the discharge capacity fading of Li-ion cells at low temperature is mainly ascribed to the charge transfer resistance increasing with temperature decreasing. In comparison, the cells containing electrolyte of 1.0 mol/L LiPF6 in EC/EMC/EA（1：1：2, mass ratio） have the highest capacity retention of 90% at-40 °C and 44.41% at-60 °C, due to its lowest charge-transfer resistance.

关键词： Li-ion cells low temperature performance electrolyte linear carboxylic ester ionic conductivity charge-transfer resistance

Study on low temperature performance of Gussasphalt on steel decks with hard bitumen

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Journal of Southeast University(English Edition) 2003年第2期19卷 160-164页

作者：杨军东南大学交通学院南京210096

Using a Hamburg wheel-track test device, the resistance to rutting of Gussasphalt is tested and compared. Gussasphalt with hard bitumen has good resistance to rutting. The related resistance abilities to cracking at low temperature of Gussasphalt are tested and compared through flexural experiments and the composite structure fatigue test with temperature dropping. Gussasphalt with high performance polymer modified bitumen has a longer fatigue life and a lower breaking temperature; they can be used in the future surfaces for steel bridge decks in Germany.

关键词： Gussasphalt surfaces for steel decks hard bitumen high performance polymer modified bitumen low temperature performance

Experimental study on low temperature performance of polymer drilling mud agents

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Global Geology 2009年第1期12卷 32-35页

作者： ZHAN Jiajia XU Huiwen CAI Hongliang College of Construction Engineering Jilin University Changchun 130026 China China Water Northeastern Investigation Design and Research Co. Ltd Changchun 130061 China

Drilling fluid additives has a major impact on rheology behavior and other performances of the drilling *** key to low temperature drilling fluids is choosing antifreeze and polymer agent which have a strong ability in resisting low *** the basis of determining glycol as antifreeze agent,the low-temperature-performance and capacities of anti-collapse of regular validity mud agents have been studied,the mechanism of anti-caving of the partially hydrolyzed polyacrylamide(PHPA),polypropylene potassium(KPA) and PAC-141 polymer additives have been also analyzed.A pilot study of compatibility between ethylene glycol and the polymers has educed that the polymers,ethylene glycol and inorganic salt are compatible,and they can significantly reduce the freezing point of drilling ***-collapse ability of the drilling mud is the results of synergistic action among the agents.

关键词： polymer low temperature performance antifreeze agent mechanism of anti-caving synergistic action

Solid State Reaction Preparation of LiFePO_4/(C+Cu) Cathode Material and Its Electrochemical performance

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Journal of Materials Science & Technology 2013年第10期29卷 937-942页

作者： Yanhong Yin Xiangnan Li Xinxin Mao Xianliang Ding Shuting Yang School of Chemistry and Chemical Engineering Henan Normal University Engineering Technology Research Center of Motive Power and Key Materials of Henan Province

Cu-C co-coated LiFePO4 （LiFePO4/（C ＋ Cu）） cathode material was successfully prepared through solid state reduction reaction. The optimized additive amount of CuO was determined by electrochemical test of series content-dependent samples. Electrochemical performances of LiFePO4/（C ＋ Cu） cathode material were investigated. Crystalline structure, morphology and electrochemical performance of the samples were characterized by X-ray diffraction, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, energy dispersive spectroscopy （EDS）, charge-discharge tests and AC impedance techniques. Results showed that crystal structure of the bulk material was not destroyed after Cu particles distributed on the surface of LiFePO4/C. With 5 wt% CuO additive, the LiFePO4/（C ＋ Cu） cathode material showed improved electrochemical performance especially at high rates and low temperature. At 25 ℃ and 0.1 C current rate, specific capacity of the Cu-coated sample reaches 161.3 mA h/g. The result was 47 mA h/g higher than that of the un-coated one. At -20 ℃, the discharge capacity of Cu-coated materials was 113.4 mA h/g at 0.1 C rate and 83.8 mA h/g at 5 C rate, which reached about 70% of that at room temperature, respectively.

关键词： LiFePO4/(C + Cu) Cu-coated low temperature performance Li-ion batteries Electrochemical performances Materials synthesis

Investigation on process mechanism of a novel energy-saving synthesis for high performance Li_(4)Ti_(5)O_(12) anode material

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Journal of Energy Chemistry 2022年第7期31卷 266-275,I0008页

作者： Guochuan Wang Hongmei Wang Guangqiang Ma Xinhe Du Liyu Du Peng Jing Yanqing Wang Kaipeng Wu Hao Wu Qian Wang Yun Zhang Department of Advanced Energy Materials College of Materials Science and EngineeringSichuan UniversityChengdu 610064SichuanChina Engineering Research Center of Alternative Energy Materials&Devices Ministry of EducationSichuan UniversityChengdu 610064SichuanChina School of Biological and Chemical Engineering Panzhihua UniversityPanzhihua 617000SichuanChina College of Polymer Science and Engineering Sichuan UniversityChengdu 610065SichuanChina

Li_(4)Ti_(5)O_(12)(LTO) anode material demonstrates superior cycling performance due to its stable spinel structure and high lithiation/de-lithiation ***,a novel energy-saving solid-phase synthesis route for LTO has been successfully designed,employing the cheap industrial intermediate product of metatitanic acid (HTO) as titanium *** the in-situ Fourier transform infrared spectroscopy (FTIR)and ex-situ X-ray diffraction (XRD),it is revealed for the first time that the amorphous crystal structure of HTO is more conducive for the Li+insertion,making it possible to prepare LTO at a relatively lower sintering *** the dehydration carbonization reaction between glucose and sulfuric acid,an ingenious strategy of glucose pre-coating is adopted to avoid the generation of Li_(2)SO_(4) impurity caused by the residual sulfuric acid on the surface of HTO,which meanwhile enhances the conductivity and inhibits the particle growth of *** obtained ALTO@C anode material consequently exhibits excellent electrochemical performance that 132.0 m Ah g^(-1)is remained even at 20 C,and ultra low decay rate of 0.015% per cycle is achieved during 1000 cycles at 2 ***,LiCoO_(2)//ALTO@C full cell delivers conspicuous low-temperature property (130.7 m Ah g^(-1)at 0.5 C and almost no attenuation after 300 cycles under-20℃).

关键词： Metatitanic acid Carbonization promoted by sulfuric acid Energy-saving low temperature performance Lithium titanate anode

Anti-cracking mechanism of diatomite asphalt and diatomite asphalt mixture at low temperature

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Journal of Southeast University(English Edition) 2009年第1期25卷 74-78页

作者：谭忆秋单丽岩房军张兴友哈尔滨工业大学交通科学与工程学院哈尔滨150090 大连海事大学交通与物流工程学院大连116026 长春公路规划勘察设计院长春130000

A kind of neat asphalt and three kinds of diatomite asphalt are tested using differential scanning calorimetry（DSC）. The anti-cracking mechanism of diatomite asphalt is analyzed by DSC and the thermal stress restrained specimen test（TSRST） of the asphalt mixtures. The results show that the low temperature performance of diatomite asphalt is better than that of neat asphalt. The glass transition temperature can reflect the low temperature performance of the diatomite asphalt better and has a good relationship with breaking temperatures. Besides, the TSRST, the bending test, the compressing test and the contraction coefficient test are used to study the low temperature performance of the diatomite asphalt mixture. The results prove that the low temperature performance of the diatomite asphalt mixture is better than that of the neat asphalt mixture. The critical bending strain energy density and the compressing strain energy density of the diatomite asphalt mixture are greater than those of the neat asphalt mixture. After adding diatomite to the asphalt mixture, the contraction coefficient is reduced. Based on the above results, the anti-cracking mechanism of the diatomite asphalt mixture is analyzed from the angle of contraction performance and breaking energy.

关键词： diatomite asphalt low temperature performance glass transition temperature differential scanning calorimetry anticracking mechanism

Study on the Efficiency and Persistence of Power Supply for Transmission Line Monitoring Device Under low temperature Conditions

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Study on the Efficiency and Persistence of Power Supply for ...