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Qiu L.,Beijing Institute of Technology | Qiu L.,Beijing Engineering Technology Research Center for Cellulose and Its Derivative Materials | Shao Z.,Beijing Institute of Technology | Shao Z.,Beijing Engineering Technology Research Center for Cellulose and Its Derivative Materials | And 12 more authors.
Cellulose | Year: 2014

This study, for the first time, synthesized carboxymethyl cellulose lithium (CMC-Li) by a two-step method and applied it to modified electrode material by electrospinning and as a binder on a lithium ion battery. By electrospinning, nano CMC-Li fiber and CMC-Li/9, 10-anthraquinone (AQ) composite fiber were obtained successfully and coated AQ electrode material. AQ was uniformly distributed in fibers, and then CMC-Li/AQ composite fiber was carbonized to obtain the carbon nanofiber/AQ/Li [CAL] composite as lithium battery anode material. Also for the first time we investigated substituting aqueous CMC-Li with different degrees of substitution (DS) for oily polyvinylidene fluoride (PVDF) as a lithium battery binder to assemble the battery with CAL for electrochemical performance tests. Compared with PVDF binder, cells with CMC-Li for a binder have excellent advantages, such as higher discharge capacity (226.4 mAh g-1), safer cycle performance, lower cost and being more eco-friendly. Furthermore, the cell with CMC-Li with high DS performed better than the cell with low DS. This method also applies to other electrode materials. © 2013 Springer Science+Business Media Dordrecht.


Qiu L.,Beijing Institute of Technology | Qiu L.,Beijing Engineering Technology Research Center for Cellulose and Its Derivative Materials | Shao Z.,Beijing Institute of Technology | Shao Z.,Beijing Engineering Technology Research Center for Cellulose and Its Derivative Materials | And 11 more authors.
Carbohydrate Polymers | Year: 2013

Cellulose derivative CMCAB was synthesized, and nanometer fiber composite material was obtained from lithium iron phosphate (LiFePO4, LFP)/CMCAB by electrospinning. Under the protection of inert gas, modified LFP/carbon nanofibers (CNF) nanometer material was obtained by carbonization in 600 C. IR, TG-DSC, SEM and EDS were performed to characterize their morphologies and structures. LFP/CNF composite materials were assembled into lithium-ion battery and tested their performance. Specific capacity was increased from 147.6 mAh g-1 before modification to 160.8 mAh g-1 after modification for the first discharge at the rate of 2 C. After 200 charge-discharge cycles, when discharge rate was increased from 2 C to 5 C to 10 C, modified battery capacity was reduced from 152.4 mAh g-1 to 127.9 mAh g-1 to 106 mAh g-1. When the ratio was reduced from 10 C to 5 C to 2 C, battery capacity can be quickly approximate to the original level. Cellulose materials that were applied to lithium battery can improve battery performance by electrospinning. © 2013 Elsevier Ltd. All rights reserved.


Qiu L.,Beijing Institute of Technology | Qiu L.,Beijing Engineering Technology Research Center for Cellulose and Its Derivative Materials | Shao Z.,Beijing Institute of Technology | Shao Z.,Beijing Engineering Technology Research Center for Cellulose and Its Derivative Materials | And 5 more authors.
Carbohydrate Polymers | Year: 2014

New cellulose derivative CMC-Li was synthesized, and nanometer CMC-Li fiber was applied to lithium-ion battery and coated with AQ by electrospinning. Under the protection of inert gas, modified AQ/carbon nanofibers (CNF)/Li nanometer composite material was obtained by carbonization in 280 C as lithium battery anode materials for the first time. The morphologies and structures performance of materials were characterized by using IR, 1H NMR, SEM, CV and EIS, respectively. Specific capacity was increased from 197 to 226.4 mAh g -1 after modification for the first discharge at the rate of 2C. Irreversible reduction reaction peaks of modified material appeared between 1.5 and 1.7 V and the lowest oxidation reduction peak of the difference were 0.42 V, the polarization was weaker. Performance of cell with CMC-Li with the high degree of substitution (DS) was superior to that with low DS. Cellulose materials were applied to lithium battery to improve battery performance by electrospinning. © 2013 Elsevier Ltd.


Lv Y.,Beijing Institute of Technology | Lv Y.,Beijing Engineering Technology Research Center for Cellulose and Its Derivative Materials | Chen Y.,Beijing Institute of Technology | Chen Y.,Beijing Engineering Technology Research Center for Cellulose and Its Derivative Materials | And 4 more authors.
Carbohydrate Polymers | Year: 2015

Homogeneous tritylation of cellulose in 1-allyl-3-methylimidazolium chloride (AmimCl) ionic liquid with triphenylmethy chloride as regents, pyridine or 1-butylimidazole (BIM) as base was investigated, and subsequent acetylation of the 6-O-functionalized products was further studied. The structure of products was analyzed by FTIR and 13C NMR spectroscopy and base influences on the structure were discussed as well. The solution with pyridine as base underwent heterogeneous-homogeneous-heterogeneous process and the obtained trityl cellulose (TC) had organized structure with trityl group located completely at C-6 position of cellulose with maximum DStrityl of nearly 1. In the case of BIM as base, the solution was homogeneous for the whole reaction, but the highest DStrityl was about 0.22, with trityl group located not only at position 6 but also partially at position 2. Subsequent acetylation of the TC led to products with a preferred functionalization of the unprotected secondary OH-groups. © 2014 Elsevier Ltd. All rights reserved.


Jia C.,Beijing Institute of Technology | Jia C.,Beijing Engineering Technology Research Center for Cellulose and Its Derivative Materials | Shao Z.,Beijing Institute of Technology | Shao Z.,Beijing Engineering Technology Research Center for Cellulose and Its Derivative Materials | And 4 more authors.
RSC Advances | Year: 2015

Cyanoethyl cellulose (CEC)/BaTiO3 (BTO) flexible nanocomposite films with enhanced dielectric properties were successfully prepared using a simple blend of CEC and BTO nanoparticles. The effects of BTO mass fraction on the morphology, microstructure, thermal stability, dynamic mechanical thermal analysis (DMTA), and mechanical properties, as well as dielectric properties of the as-prepared nanocomposite films were investigated. The results showed that the BTO nanoparticles of about 100 nm in size were dispersed homogenously in the CEC matrix without obvious agglomeration. The obtained nanocomposite films possessed higher thermal stability than the original CEC. DMTA revealed that the addition of BTO nanoparticles enhanced the glass transition temperature of the nanocomposite films. The mass fractions of the BTO nanoparticles had a significant effect on the tensile strength and elongation at break of the nanocomposite films. The dielectric permittivity of the nanocomposite films decreased gradually with frequency, the dielectric loss decreased sharply at low frequency, and had little change at higher frequency. The dielectric permittivity of the nanocomposite films gradually increased with increasing mass fraction of BTO nanoparticles at all of the frequencies. The dielectric loss of the nanocomposite films had a tendency to decrease with increasing mass fraction of BTO nanoparticles at 103 Hz, but the dielectric loss almost remained unchanged at the higher frequency. When the mass fraction of BTO nanoparticles was 90%, the nanocomposite film had the biggest dielectric permittivity of 27.24 at 103 Hz, the corresponding dielectric loss was 0.3023. © 2015 The Royal Society of Chemistry.

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