Lithium Acrylate Research Articles

Ionic Conduction and Dielectric Response of Nanoparticle-Coupled Hydrogel Network Polymer Electrolytes

The molecular level understanding of ion and polymer dynamics in nanoparticle-coupled hydrogel network polymer electrolytes is investigated by linear dielectric and viscoelastic measurements covering broad ranges of frequency and temperature. We prepare hydrogel polymer electrolytes (HPEs), composed of Li+ conducting hydrophilic poly(lithium acrylate) (PLiA) as the HPE matrix and vinyl-functionalized silica nanoparticles (NPs) as cross-linking points, via radical polymerization and sol–gel reaction. The NP content variation leads to changes in ionic conductivity (σDC), dielectric constant (εs), relaxation frequency, and elastic modulus, which are important characteristic factors for understanding ion transport. From the physical model of electrode polarization (EP), allowing for the determination of the number density of simultaneously conducting ions and their mobility, the NP-containing HPEs (HPE-NP) have simultaneously higher conducting ion concentration (p) and mobility (μ), resulting in higher ionic conductivity (σDC ∼ pμ), compared to the HPE without NPs. The temperature dependence of p and μ follows Arrhenius (thermally activated) and Vogel–Fulcher (segmentally driven) temperature dependences, respectively. In addition to the lower frequency EP, the HPEs show higher frequency relaxation (α2), attributed to ions rearranging. NP incorporation leads to faster α2 relaxation and higher static dielectric constant εs (shorter Bjerrum length lB). Time–temperature superposition (tTS) works well for these electrolytes and is applied to construct master curves of viscoelasticity and in-phase conductivity. In the end, the NP-containing HPE-based supercapacitor is fabricated using carbon nanotube yarn (CNTY) electrodes and shows stable electrochemical performance, demonstrating that our HPE can be a solid-state polymer electrolyte for energy storage devices.

Tailoring molecular interaction in heteronetwork polymer electrolytes for stretchable, high-voltage fiber supercapacitors

Mechanically and electrochemically stable all-solid-state supercapacitors are of great interest in the field of wearable and portable electronic devices. However, when conventional liquid or gel electrolytes are used in supercapacitors, their discontinuous functions appear in harsh external environments. Here, we prepare freeze-tolerant heteronetwork nanohybrid polymer electrolytes (NPEs), composed of hydrophilic poly(lithium acrylate) (PLiA) containing mobile lithium countercations and mechanically robust silica nanoparticles (SNs) serving as stress buffers, via sol–gel reaction and radical polymerization. The combination of PLiA and SN provides NPE (PLiA-SN) with high room temperature ionic conductivity (up to σDC ∼ 10-1 S/cm), which not only remains 100% even after 700% elongation, but also exhibits high ionic conductivity at low temperatures (σDC = 4×10-3 S/cm at 0 °C). This is because Li+ binds strongly to water, thereby preventing water evaporation and crystallization, as revealed by density functional theory (DFT) calculations. The cross-linking of SNs with PLiA chains also gives the resultant NPE superelasticity and self-healing property. The optimized NPE is assembled with metal–organic framework derived carbon (MDC)-coated carbon nanotube yarn (MDC@CNTY) hybrid electrodes, possessing both high charge storage capability and superior mechanical properties, to fabricate high-performance all-solid-state fiber supercapacitors (FSCs). The assembled FSC delivers a high specific capacitance of 51 F/g, high power (6 kW/kg, 27 mW/cm2, 1202 μW/cm) and energy (44 Wh/kg, 0.2 mWh/cm2, 9 μWh/cm) densities, as well as a wide operating voltage window as high as 2.5 V. Moreover, the electrochemical performance of the FSC is maintained under different stretching strains, various degrees of bending, and cutting/healing cycles, and still retains ∼ 92% capacity even at a low temperature (-10 °C), demonstrating excellent mechanical, thermal, and electrochemical stability. This work provides an effective strategy for designing energy storage devices that are sufficiently stretchable, bendable, and reliable for use in extreme environments.

The effect of inorganic nanoparticles on ion conduction in poly(lithium acrylate)-based composite polymer electrolytes for energy storage devices

Recently, considerable researches are conducted to develop promising polymer electrolytes for Li-ion batteries (LIBs). Herein, we prepared poly(lithium acrylate) (PAALi)-based composite polymer electrolytes (CPEs) containing alumina (Al2O3) nanoparticles. The addition of inorganic nanoparticles into the PAALi matrix can not only improve CPE’s ionic conductivity ( at 303 K), but also enhance CPE’s mechanical properties due to the nanoparticles acting as cross-linkers between the PAALi chains. We systematically investigated the influences of inorganic nanoparticle types (pure alumina vs. vinyl functionalized alumina) and contents on ionic conduction and mechanical properties of PAALi-based CPEs.

A delicately designed functional binder enabling in situ construction of 3D cross‐linking robust network for high‐performance Si/graphite composite anode

AbstractThe silicon (Si)‐based anodes suffer from large volume expansion in the lithiation process. Aiming at improving the cycling stability of a Si/graphite composite anode processed by chemical vapor deposition (CVD) method, a functional aqueous binder was delicately designed and synthesized via an aqueous copolymerization of lithium acrylate and vinyl triethoxy silane (VTEO). The PAA‐VTEO binder can in situ react with the silanol groups on the surface of Si nanoparticles to form a robust 3D cross‐linked network. The resulting extremely high modulus and hardness of this integrated 3D network structure effectively restrained the volume expansion effect and significantly enhanced the electrochemical cycling stability of the CVD‐Si@graphite composite anode. This work will provide new perspectives in designing functional binder for Si‐based anodes.

A dual-functional poly(vinyl alcohol)/poly(lithium acrylate) composite nanofiber separator for ionic shielding of polysulfides enables high-rate and ultra-stable Li-S batteries

Despite the high theoretical specific capacity, the main challenges of rechargeable lithium-sulfur (Li-S) batteries, including the unceasing shuttle of soluble lithium polysulfides (LiPSs) and severe Li corrosion, seriously hinder their commercial and practical applications. Herein, a bifunctional polyvinyl alcohol/poly(lithium acrylate) (C-PVA/PAA-Li) composite nanofiber separator is developed to address the main challenges in Li-S batteries by simultaneously allowing rapid lithium ion transport and ionic shielding of polysulfides. The C-PVA/PAA-Li composite nanofiber membrane is prepared via the facile electrospinning strategy, followed by thermal crosslinking and in-situ lithiation processes. Differing from the conventional Celgard-based coating methods accompanied by impaired lithium ion transport efficiency, the C-PVA/PAA-Li composite nanofiber membrane possesses well-developed porous structures and high ionic conductivity, thus synergistically reducing the charge transfer resistance and inhibiting the growth of lithium dendrites. The resulting Li-S batteries exhibit an ultra-low fading rate of 0.08% per cycle after 400 cycles at 0.2 C, and a capacity of 633 mAhg−1 at a high current density of 3 C. This study presents an inspiring and promising strategy to fabricate emerging dual-functional separators, which paves the pathway for the practical implementation of ultra-stable and reliable Li-S battery systems.

Partially lithiated ternary graft copolymer with enhanced elasticity as aqueous binder for Si anode

AbstractPartially lithiated ternary graft copolymers were synthesized through free radical graft polymerization of acrylic acid (AA), lithium acrylate (LiAA) and hydroxyethyl acrylate (HEA) onto polyvinyl alcohol (PVA). With optimized feeding molar ratio of AA/LiAA/HEA (2:1:2), the ternary graft copolymer with partial lithiation shows the best flexibility, elasticity and adhesion strength comparing to PVA‐g‐PAA and PVA‐g‐P(AA‐HEA) when used as aqueous binder for Si anode. The Si anode using PVA‐g‐P(AA‐LiAA‐HEA) with the optimized molar ratio of AA‐LiAA‐HEA exhibits better cycling stability and rate performance, delivering a capacity of 2265 mAh g−1 with a capacity retention of 82.4% after 200 cycles at 1A g−1. Even at a high current of 10 A g−1, the Si electrode still obtained a high capacity of 1300 mAh g−1.

Polypropylene separator coated with a thin layer of poly(lithium acrylate‐co‐butyl acrylate) for high‐performance lithium‐ion batteries

ABSTRACTIn this paper, poly(lithium acrylate‐co‐butyl acrylate) [P(AALi‐co‐BA)] was synthesized, and a P(AALi‐co‐BA)‐coated polypropylene (PP) separator was prepared by a simple dip‐coating process. In contrast to the conventional thick, dense gel polymer coating layer, a thin P(AALi‐co‐BA) layer was formed on the PP separator, which had less influence on the pore structure of the original PP separator and was beneficial for the migration of lithium ions through the separator. Furthermore, the AALi units in the copolymer could improve the wettability of the separator, while the BA units provided the separator with strong adhesion to the electrodes. As expected, the modified separators showed good wettability, high ionic conductivity, and excellent interface stability. In addition, the cycle stability and rate performance were also improved significantly. This facile, affordable, and effective method has great application potential for the modification of polyolefin‐based separators. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46423.

Fabrication of a Novel Water Swellable Styrene-butadiene Rubber through the In-situ Polymerization of Lithium Acrylate

A novel water-swellable rubber (WSR) was prepared by blending styrene butadiene rubber (SBR) with dicumyl peroxide (DCP) and unsaturated carboxylic acid salt lithium acrylate (LiAA). The mechanical properties and water absorption behavior of WSR were studied. The results showed that LiAA was developed into polylithiumacrylate (PliAA) during the process of SBR vulcanization through in-situ polymerization, leading to the improvement of the mechanical properties and water absorption performance. The optimum usages of DCP and triallyl isocyanurate (TAIC) to attain the highest water swelling ratio for WSR were 3 and 1 phr, respectively. In addition, the tensile strength and the hardness of WSR were also enhanced by incorporating DCP or TAIC.

Composite Polymer Electrolyte Containing Core-Shell Structured SiO2(Li+) Particles for Suppressing Lithium Dendrite Growth and Improving High Temperature Cycling Stability of LiNi0.5Mn1.5O4

The most widely used electrolyte for lithium-ion batteries is lithium hexafluorophosphate (LiPF6) in a mixture of organic carbonate solvents due to its high conductivity, good electrochemical stability and acceptable cycle performance at low temperatures [1]. However, the use of liquid electrolytes in lithium batteries has many drawbacks, such as high flammability of organic solvents, possibility of leakage and poor thermal stability [2, 3]. Among the potential electrolytes for lithium batteries, polymer electrolyte has received considerable attention due to high ionic conductivity and superior thermal safety with no electrolyte leakage [4]. However, polymer hosts lose their mechanical strength when they are plasticized with liquid electrolyte solution, leading to serious problems in terms of cycle life and safety [5]. In this study, in order to obtain polymer electrolytes with enhanced mechanical strength and good electrochemical properties, core-shell structured SiO2 nanoparticles containing poly(lithium acrylate) in the shell were synthesized. They were used as functional fillers in preparing composite polymer electrolytes for suppressing lithium dendrite growth and preventing HF generation in the electrolyte. The composite polymer electrolytes prepared with SiO2(Li+) particles exhibited high ionic conductivity, good thermal stability and favorable interfacial characteristics. The lithium metal polymer cells composed of lithium metal negative electrode and LiNi0.5Mn1.5O4 positive electrode are assembled and their cycling performances are evaluated. The cells assembled with the composite polymer electrolyte exhibited superior cycling performance both at ambient temperatures and at elevated temperature.

Composite Gel Electrolytes for Suppressing Lithium Dendrite Growth and Improving Cycling Performance of LiNi0.5Mn1.5O4 Electrodes

Core-shell structured SiO2 particles with a poly(lithium acrylate) shell were synthesized and used in preparing a composite gel electrolyte. The composite gel electrolyte exhibited high ionic conductivity and favorable interfacial characteristics at the lithium electrode. The use of a composite gel electrolyte containing SiO2(Li+) particles effectively suppressed both the dendrite growth of lithium and dissolution of transition metals from the active LiNi0.5Mn1.5O4 material. The lithium metal polymer cell composed of a lithium negative electrode and a LiNi0.5Mn1.5O4 positive electrode delivered a high discharge capacity of 136.6 mAh g−1 and exhibited good capacity retention.

High-Performance Lithium-Ion Polymer Cells Assembled with Composite Polymer Electrolytes based on Core-Shell Structured SiO2 Particles Containing Poly(lithium acrylate) in the Shell

Core-shell structured SiO2 nanoparticles containing poly(lithium acrylate) in the shell were synthesized and used as functional fillers in composite polymer electrolytes for lithium-ion polymer cells. The composite polymer electrolytes prepared with SiO2(Li+) particles exhibited high ionic conductivity, good thermal stability, and favorable interfacial characteristics. By using these composite polymer electrolytes, lithium-ion polymer cells composed of a graphite negative electrode and a LiNi0.6Co0.2Mn0.2O2 positive electrode were assembled, and their cycling performance was evaluated. The cells assembled with composite polymer electrolytes containing a proper amount of SiO2(Li+) particles exhibited good cycling performance at both at ambient and elevated temperatures.

Polymer electrolytes based on polyanionic lithium salts

Abstract Polymer electrolytes composed of poly(ethylene oxide) and a polyanionic lithium salt are prepared, and electrochemical and thermal properties were investigated in the absence and presence of BF 3 ·OEt 2 . The addition of BF 3 ·OEt 2 increases the ionic conductivities, and the lithium ion transference number of the polymer electrolyte for the PEO/poly(lithium acrylate) (PLA) and PEO/poly(lithium vinylsulfonate) (PLVS) system were higher than that of PEO/lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) system. However, ionic conductivities of the polymer electrolyte in the presence of BF 3 ·OEt 2 for the PEO/PLVS system were higher than that for the PEO/PLA system below 50 °C, due to the suppression of the crystallization of PEO. It was found that the structure of functional group in polyanionic lithium salts significantly affect electrochemical and thermal properties of polymer electrolytes.

Effects of LiClO<sub>4 </sub>on the Characteristics and Ionic Conductivity of the Solid Polymer Electrolytes Composed of PEO, LiClO<sub>4</sub> and PLiAA

Solid polymer electrolytes (SPEs) which were composed of poly (ethylene oxide) (PEO), poly (lithium acrylate) (PLiAA), and LiClO4 were prepared in order to investigate the influence of LiClO4 content on the ionic conductivity of the electrolyte. All of the membranes were investigated by XRD, DSC, and EIS, et.al. The dependence of SPEs conductivity on temperature was measured, and the maximum ionic conductivity is 5.88×10-6 S/cm at 293 K for membrane which is composed of PEO+PLiAA+15wt% LiClO4. The electrochemical stability window of the PEO+PLiAA+15wt% LiClO4 is 4.75 V verse Li.

Preparation and Characterization of a Novel Gel Polymer Membrane Based on a Tetra-Copolymer

A acrylonitrile (AN)-methyl acrylate (MMA)-methoxy polyethylene glycol(350) monoacrylate (MPGA)-lithium acrylate (LiAc) tetra-copolymer was synthesized by emulsion polymerization, and phase inversion technique was adopted to prepare the as prepared polymer based microporous membrane. The gel polymer electrolytes (GPEs) were obtained by soak the as-prepared microporous membrane into 1M LiPF6/ (EC (ethylene carbonate) + DEC (diethylene carbonate)) (1:1 vol) electrolyte. FTIR, NMR and TGA/DSC measurements are used to character the components and structure of the polymer. The GPE’s ionic conductivity exceeds 3.0×10-3S/cm at ambient temperature, and this system also shows a sufficient electrochemical stability with a decomposition voltage as much as 6.0V vs Lithium(Li)/Li+ to allow far wider operation in the rechargeable lithium-ion polymer batteries. What’s more, this membrane also shows good characters in battery’s charge-discharge cycles.

Preparation and Performance of Novel Acrylonitrile (AN)-based Copolymer Gel Electrolytes for Lithium Ion Batteries

A novel acrylonitrile (AN)-based copolymer, P(acrylonitrile(AN)- methyl methacrylate(MMA)-methoxy polyethylene glycol(350) monoacrylate(MPGA)-lithium acrylate(LiAc)) (PAMMGLiAc) gel electrolytes was prepared in this paper. The physical properties of the AN-based copolymer membranes were characterized by IR, NMR, TGA, DSC and tensile test. The electrochemical characteristics of the AN-based gel electrolytes were investigated by electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV). The results show that the gel electrolytes have high ionic conductivity over 2×10-3S/cm at room temperature, good mechanical properties and a sufficient electrochemical stability with a decomposition voltage as high as 6V vs. Li. The Li/gel electrolyte/LiFePO4 coin cells with the prepared copolymer gel electrolytes also showed a good charge/discharge performance.

Solid polymer electrolytes based on poly(lithium carboxylate) salts

The ionic conductivity, lithium ion transference number, electrochemical stability, and thermal property of solid polymer electrolytes composed of poly(ethylene oxide) (PEO) and poly(lithium carboxylate)s, (poly(lithium acrylate) (Poly(Li-A)) or poly(lithium fumarate) (Poly(Li-F)), with and without BF3·OEt2 were investigated. The ionic conductivities of all solid polymer electrolytes were enhanced by one to two orders of magnitude with addition of BF3·OEt2 because the dissociation of lithium ion and carboxylate anion was promoted by the complexation with BF3. The lithium ion transference number in the solid polymer electrolytes based on poly(lithium carboxylate)s showed relatively high values of 0.41–0.70, due to the suppression of the transport of counter anion by the use of a polymeric anion. The solid polymer electrolytes with addition of BF3·OEt2 showed good electrochemical stability.

Synthesis of Highly Transparent Lithium Ferrite Nanoparticle/Polymer Hybrid Self-standing Films Exhibiting Faraday Rotation in the Visible Region

A lithium ferrite nanoparticle/ethyl(hydroxyethyl)cellulose (EHEC) hybrid was synthesized via in situ hydrolysis of prepolymerized iron(III) 3-allylacetylacetonate (IAA) and lithium acrylate (LA) in the presence of EHEC below 100 °C. The hybrid film was flexible and self-standing and showed high transmittance in the visible region. The crystallite size of lithium ferrite in the hybrid increased from 2.7 to 3.8 nm with decreasing amounts of EHEC. Nanosized lithium ferrite particle/EHEC hybrid showed a BH curve with no remanence at room temperature. The hybrid was superparamagnetic with a blocking temperature of 13 K. The absorption edge of the hybrid film was blue-shifted compared with bulk lithium ferrite. The blue-shift increased with decreasing crystallite size, which was controlled by the amount of EHEC. The self-standing film exhibited a Faraday rotation depending upon the magnetic field. The curve for the specific Faraday rotation (F) versus magnetic field corresponded to that for magnetization versu...

Preparation and characterization of gel polymer electrolytes based on acrylonitrile–methoxy polyethylene glycol (350) monoacrylate–lithium acrylate terpolymers

The acrylonitrile (AN)–methoxy polyethylene glycol (350) monoacrylate (MPGA)–lithium acrylate (LiAc) copolymers (PAMGLiAc) was synthesized by emulsion polymerization. Phase inversion technique was used to prepare the PAMGLiAc microporous membrane. The gel polymer electrolytes (GPEs) with the PAMGLiAc were obtained by the copolymer microporous membrane soaking liquid electrolyte. The component and structure of the PAMGLiAc were characterized by IR, NMR and TGA/DSC measurement. The electrochemical characteristics of the PAMGLiAc gel electrolytes were investigated in terms of different composition. The ionic conductivity exceeded 2.0 × 10 −3 S/cm at ambient temperature, and this system also showed good mechanical properties and a sufficient electrochemical stability with a decomposition voltage as much as 5 V vs. Li to allow far wider operation in the rechargeable lithium-ion polymer batteries.

In situ synthesis of lithium ferrite nanoparticle/polymer hybrid

Lithium ferrite particle/organic hybrid was synthesized in situ from iron–organic and lithium–organic compounds below 100 °C. Spinel ferrite particle/organic hybrid was synthesized by hydrolyzing a mixture of iron (III) 3-allylacetylacetonate (IAA) and lithium acrylate (LA). X-ray diffraction analysis revealed that the crystallinity of spinel particle was dependent on the polymerization treatment and the hydrolysis conditions. The saturation magnetization of hybrid increased with increasing methylhydrazine and water amount of hydrolysis. Nanocrystalline lithium ferrite particle about 5 nm was dispersed in the organic matrix. The hybrid showed neither remanence nor coercive force at room temperature. The magnetization versus field/temperature H/T curves from 100 to 300 K were superimposed on the same curve and satisfied the Langevin equation. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization curve revealed that the blocking temperature was about 75 K. The remanent magnetization and coercive field of the hybrid were 8.9 A·m2/kg and 26.3 kA/m, respectively, at 10 K.

Preparation and Characterization of Poly(acrylonitrile-methoxy polyethylene glycol (350) monoacrylate-lithium acrylate)

采用乳液聚合方法制备了锂离子电池凝胶电解质用丙烯腈-甲氧基聚乙二醇（350）单丙烯酸酯-丙烯酸锂共聚物.利用红外光谱（IR）,差示扫描量热法（DSC）对共聚物结构进行了表征.利用倒相法制备了共聚物微孔膜,使聚（丙烯腈-甲氧基聚乙二醇（350）单丙烯酸酯）共聚物的溶解性能得到了显著提高,同时,还改善了膜的收缩性.采用交流阻抗方法测试了凝胶电解质膜在室温下的电导率,结果表明,该凝胶电解质具有较高的离子电导率,能满足现有锂离子电池使用要求.