Water-soluble Sodium Carboxymethyl Cellulose Research Articles

(Invited) Transparent Electrode and Magnetic Permalloy Made from Novel2 Nanopaper

We report a novel partial dissolution strategy to liberate uniform cellulose nanofibers with diameter of 5-10 nm from macroscopic cellulose fibers and promote separation of nanofibers in an aqueous environment by forming water-soluble sodium carboxymethylcellulose (CMC) through heterogeneous sodium acetoxylation of cellulose. With the obtained cellulose nanofibers, we fabricated nanopapers which exhibit a high optical transparency of 90.5 % (550 nm) with promising mechanical properties and high thermal stability. By directly depositing Ag nanowires on a wet nanofiber sheet, we fabricated a flexible transparent electrode with 86.5 % (550 nm) transparency and 26.2 Ohm/sq sheet resistance (Rs). Meanwhile, we studied the magnetic properties of sputter deposited thin film of permalloy on nanopaper which exhibited a similar magnetic coercivity and a close saturation magnetization to conventional silicon dioxide-based permalloy.

Graphite//LiNi0.5 Mn1.5 O4 Cells Based on Environmentally Friendly Made-in-Water Electrodes.

The performance of graphite//LiNi0.5 Mn1.5 O4 (LNMO) cells, both electrodes of which are made using water-soluble sodium carboxymethyl cellulose (CMC) binder, is reported for the first time. The full cell performed outstandingly over 400 cycles in the conventional electrolyte ethylene carbonate/dimethyl carbonate-1 m LiPF6 , and the delivered specific energy at the 100th, 200th, 300th, and 400th cycle corresponded to 82, 78, 73, and 66 %, respectively, of the initial energy value of 259 Wh kg-1 (referring to the sum of the two electrode-composite weights). The good stability of high-voltage, LNMO-CMC-based electrodes upon long-term cycling is discussed and the results are compared to those of LNMO-composite electrodes with polyvinylidene fluoride (PVdF). LNMO-CMC electrodes outperformed those with PVdF binder, displaying a capacity retention of 83 % compared to 62 % for the PVdF-based electrodes after 400 cycles at 1 C. CMC promotes a more compact and stable electrode surface than PVdF; undesired interfacial reactions at high operating voltages are mitigated, and the thickness of the passivation layer on the LNMO surface is reduced, thereby enhancing its cycling stability.

Thermal, Rheological, Mechanical and Morphological Behavior of High Density Polyethylene and Carboxymethyl Cellulose Blend

In this study water soluble sodium carboxymethyl cellulose (CMC) was blended with high density polyethylene (HDPE) by peroxide-initiated melt compounding technique. The compatibility of the blended polymers were carried out by silane crosslinking agent. A series of blends were prepared by varying the CMC contents up to a maximum of 50 phr. The physical properties of non-crosslinked and crosslinked blends were investigated in detail. FTIR analysis of crosslinked blend confirmed the presence of Si–O–Si and Si–O–C absorption peaks at 1050 and 1159 cm−1. Thermal stability of crosslinked blends improved as compared to its non-crosslinked congener. Rheological study of crosslinked blends illustrated high complex viscosity and dynamic shear storage modulus. The tensile strength of virgin polyethylene was 8.1 MPa whereas the maximum tensile strength of 19.6 MPa was observed in crosslinked blend. Similarly lower deformation was observed in crosslinked blends under static load. Scanning electron microscopy of crosslinked formulations also showed strong adhesion between the polymers interface. The compatibility of HDPE and CMC is attributed to both free radical and condensation reactions.

Transparent Electrode and Magnetic Permalloy Made from Novel Nanopaper.

We report a novel partial dissolution strategy to liberate uniform cellulose nanofibers with diameter of 5-10 nm from macroscopic cellulose fibers and promote separation of nanofibers in an aqueous environment by forming water-soluble sodium carboxymethylcellulose (CMC) through heterogeneous sodium acetoxylation of cellulose. With the obtained cellulose nanofibers, we fabricated nanopapers which exhibit high optical transparency of 90.5% (@550 nm) with promising mechanical properties and high thermal stability. By directly depositing Ag nanowires on a wet nanofiber sheet, we fabricated a flexible transparent electrode with 86.5% (@550 nm) transparency and 26.2 Ω/sq sheet resistance (Rs). Meanwhile, we studied the magnetic properties of sputter deposited thin film of permalloy on nanopaper which exhibited a similar magnetic coercivity and a close saturation magnetization to conventional silicon dioxide-based permalloy.

Oxygen-Rich Binder Improves Vulcanized Polyacrylonitrile Cathodes for Li-S Batteries

Lithium sulfur batteries have very high theoretical energy density. However, the cyclic stability of carbon-sulfur cathode is seriously hindered by the notorious polysulfide dissolution. Vulcanized polyacrylonitrile is an alternative to carbon-sulfur cathodes where the carbon and sulfur are covalently bonded resulting in much improved stability. Although water-soluble binders are being used widely to stabilize carbon-sulfur cathodes, we observe here that oxygen-rich water-soluble binder can instead facilitate the high-rate performance of vulcanized polyacrylonitrile cathode. In this study, oxygen-rich water-soluble sodium carboxymethyl cellulose (NaCMC) is selected as binder for vulcanized polyacrylonitrile (PANS) cathode. Comparing with traditional oxygen-free PVDF binder, NaCMC shows a preference in fixing active materials and enabling better surface wettability. A high capacity of 938 mA h/g for sulfur is retained after 450 cycles at 0.9C (1C=1675 mA/g). In addition the capacity from NaCMC electrode at 4.5 C rate reaches 677 mA h/g, which is much higher than that obtained with PVDF binder (nearly zero at 4.5C). Our study here reveals the facilitated redox chemistry of PANS cathode by using oxygen-rich binders. The origin is believed relevant to the affinity of oxygen functional groups to lithium polysulfides in terms of chemical adsorption and interfacial charge transfer.

Cyanoethylated Carboxymethyl Chitosan as Water Soluble Binder with Enhanced Adhesion Capability and electrochemical performances for LiFePO4 Cathode

Cyanoethylated carboxymethyl chitosan (CN-CCTS) has been synthesized through a straightforward cyanoethylation reaction by reacting CCTS with acrylonitrile in NaOH aqueous solution. CN-CCTS shows improved adhesion strength of 0.047N/cm as compared with 0.013N/cm for CCTS after introducing cyanoethyl group in the chemical structure of CCTS. The electrochemical performances of LiFePO4 electrode with CN-CCTS binder have been investigated and compared with those using water soluble sodium carboxymethyl cellulose (CMC) and non-aqueous polyvinylidene difluoride (PVDF) binder. LiFePO4 electrode with CN-CCTS exhibits better cycling stability and rate capability, retaining 56.3% capacity of C/5 at 5C rate as compared with 48.4% and 32.8% for CMC and PVDF, respectively. Cyclic voltammetry and electrochemical impedance spectroscopy measurement reveal that LiFePO4 electrode with CN-CCTS has a more favorable electrochemical kinetics than that with CMC and PVDF, thus better rate capability.

The polyacrylic latex: an efficient water-soluble binder for LiNi1/3Co1/3Mn1/3O2 cathode in li-ion batteries

The polyacrylic latex (LA132) was firstly reported as a water-soluble binder for LiNi1/3Co1/3Mn1/3O2 (NCM) cathode in Li-ion battery. The electrochemical performances of NCM cathode with LA132 binder were investigated and compared with the conventional water-soluble sodium carboxymethyl cellulose (CMC) and commercial non-aqueous polyvinylidene difluoride (PVDF). NCM cathode with LA132 binder exhibited a much higher specific capacity of 146 mAh g−1 and capacity retention of 96.4 % after 100 cycles as compared with 122 mAh g−1/88 % and 121 mAh g−1/75% for the NCM electrode with CMC and PVDF, respectively. In addition, NCM cathode with LA132 binder exhibited better rate capability than that of CMC and PVDF, e.g., retaining 34.3 % capacity of C/5 at 5 C rate as compared with 28.5 and 10.9 % for CMC and PVDF, respectively.

Investigation on Carboxymethyl Chitosan as New Water Soluble Binder for LiFePO4 Cathode in Li-Ion Batteries

Carboxymethyl chitosan (C-CTS) was firstly reported as a water soluble binder for LiFePO4 cathode in Li-ion batteries. The electrochemical performances of LiFePO4 cathode with C-CTS binder was investigated and compared with the conventional water-soluble sodium carboxymethyl cellulose (CMC) and the commercial non-aqueous polyvinylidene difluoride (PVDF). LiFePO4 cathode with C-CTS exhibited a comparable cycling performance, but better rate capability than that of CMC and PVDF, retaining 65% capacity of C/5 at 5C rate as compared with 55.9% and 39.4% for CMC and PVDF, respectively. In addition, LiFePO4 cathode with C-CTS exhibited excellent cycling performance at 60°C, retaining 91.8%/62.1% capacity after 80 cycles at 1C/10C, respectively.

Micro/nano-structured SnS2 negative electrodes using chitosan derivatives as water-soluble binders for Li-ion batteries

Micro/nano-structured SnS2 was prepared by a hydrothermal method using biomolecular l-cysteine and SnCl4·5H2O as sulfur source and tin source, respectively. The electrochemical performances of SnS2 electrodes were investigated using water-soluble binders of carboxymethyl chitosan (C-chitosan) and chitosan lactate, and compared with the conventional water-soluble sodium carboxymethyl cellulose (CMC) and non-aqueous polyvinylidene difluoride (PVDF). SnS2 electrode using the water-soluble binders (C-chitosan, chitosan lactate, and CMC) showed higher initial coulombic efficiency, larger reversible capacity, and better rate capabilities than that of PVDF. In addition, SnS2 electrode using C-chitosan binder exhibited somewhat worse cycling stability, but better rate capability at a high rate of 5C than CMC.

Study of the electrochemical behavior at low temperatures of green anodes for Lithium ion batteries prepared with anatase TiO2 and water soluble sodium carboxymethyl cellulose binder

The electrochemical behavior at low temperatures of anatase TiO2 electrodes for Lithium ion batteries have been evaluated by galvanostatic cycles in the temperature range 20 to −30°C. Two different manufacturing processes have been used to prepare anatase anodes containing water soluble sodium carboxymethyl cellulose (CMC) or poly(vinilydene fluoride) (PVDF) as binder.The low temperature performances at different charge/discharge rates of TiO2/CMC and TiO2/PVDF electrodes are compared and discussed in terms of irreversible capacity loss (ICL) at the first cycle, capacity retention and reversible capacity. The kinetics of the electrodes containing CMC or PVDF is evaluated by Electrochemical Impedance Spectroscopy.

High performance, environmentally friendly and low cost anodes for lithium-ion battery based on TiO 2 anatase and water soluble binder carboxymethyl cellulose

The challenge of producing lithium-ion batteries meeting performance requirements and low environmental impact is strictly related to the choice of materials as well as to the manufacturing processes. Most electrodes are currently prepared using poly(vinilydene fluoride) (PVDF) as binder. This fluorinated polymer is expensive and requires the use of a volatile and toxic organic solvent such as N-methyl-pyrrolidone (NMP) in the processing. Water soluble sodium carboxymethyl cellulose (CMC) can be a suitable substitute for PVDF as binder for both anodes and cathodes eliminating the necessity of NMP and thus decreasing the cost and the environmental impact of battery production. In this work, CMC has been successfully used to prepare efficient and stable anatase TiO 2 anodes by optimizing the electrode manufacturing process in terms of composition and compression. The stability and the high rate performances of the TiO 2/CMC are described and compared with those of TiO 2/PVDF electrodes. The compatibility of the TiO 2/CMC with a LiFePO 4 cathode in a full-cell is also reported.

Hydrophilic Co–Pt Alloy Nanoparticles: Synthesis, Characterization, and Perspectives

Hydrophilic Co–Pt alloy nanoparticles nearing the equiatomic ratio and dispersedin water-soluble sodium carboxymethyl cellulose were synthesized by the aqueous reduction of CoCl2⋅6H2O and [Pt(NH3)4]Cl2⋅H2O with NaBH4 in presence of the cellulosic derivative. The as-received Co–Pt nanoparticles in the cellulosic matrix possess a disordered fcc structure that, upon calcination under an Ar atmosphereand carbonization of the cellulosic mantle of the particles, transformed to an ordered fcc phase. Both as-synthesized and calcined samples are magnetically soft at room temperature and exhibit a strong magnetic response when a magnetic field is applied. On account of the chemical composition of the carboxymethyl cellulose, the coated Co–Pt nanoparticles are easily soluble in water in high concentrations and exhibit interesting ion-exchange properties.