PEO LiClO4 Research Articles

Dielectric relaxation studies of poly(ethylene oxide) with the addition of salt or nanofiller

AbstractPoly(ethylene oxide) (PEO)–lithium perchlorate (LiClO4) serves as the classical model of polymer–salt systems with good polymer–salt molecular interaction at low salt concentration, whereas titanium dioxide (TiO2) without any surface treatment when added to PEO serves as a classical model of polymer–filler systems with weak polymer–filler molecular interaction. The correlation of molecular interactions of polymer–salt or polymer–filler with thermal properties of the systems, which govern the formation of morphologies of the systems, was attempted in a previous study. Hence, this work focuses on the correlation of morphologies and dielectric relaxation properties of PEO with the addition of LiClO4 or TiO2 investigated using polarized optical microscopy and electrochemical impedance spectroscopy over the frequency range from 50 Hz to 1 MHz at 25 °C. The effects of the addition of LiClO4 or TiO2 on the dynamics and relaxations of the polymer chain of PEO are discussed empirically following the fluctuation–dissipation effects from the common electrochemical terms and equivalent circuit model. The PEO–LiClO4 system seems to be one of the promising polymer electrolytes for application in lithium rechargeable batteries where the charged entities may arise from the interaction of salt with the ether oxygen of PEO in the amorphous region. Meanwhile, the PEO–TiO2 system may be analogous to a polar polymer with longitudinal dipoles along the PEO backbone, ethylene oxide monomers (from PEO) of which may represent the molecular dipole or charged entity. The findings show that the transport of charged entities in the PEO systems after the addition of LiClO4 or TiO2 is dominated by short‐range motion at room temperature. © 2022 Society of Industrial Chemistry.

A facile preparation of PEO–LiClO4–fumed SiO2 composite solid-state electrolyte with improved electrochemical performance for lithium-metal batteries

PEO–LiClO4–fumed SiO2 composite solid-state electrolyte is successfully fabricated with superior 3 migration capacity to Li+ and improved electrochemical performance for lithium-metal battery by a 4 facile preparation process.

Electrospun poly(ethylene oxide) nanofibrous composites with enhanced ionic conductivity as flexible solid polymer electrolytes

Solid polymer electrolytes (SPEs) have great potential to address the safety issues of lithium (Li)-ion batteries when compared with conventional liquid electrolytes, which makes them a promising alternative for next-generation high-energy batteries. In this work, poly(ethylene oxide)-lithium perchlorate (PEO–LiClO4) polymer electrolytes for Li-ion batteries were prepared using electrospinning. The crystallinity, ionic conductivity as well as mechanical properties were investigated. Ionic conductivities and mechanical properties of PEO–LiClO4 based SPE have been obviously increased by incorporating modified TiO2 nanofibres (TNFs) than TiO2 nanoparticles (TNPs), due to that both TNFs and TNPs can decrease the crystalline phase concentration of PEO and increase segmental flexibility of PEO. The SPE with 3 wt% TNFs exhibits the highest conductivity of 5.308 × 10−5 S cm−1 at 20°C and higher tensile strength of 13.8 MPa. These results highlight the potential of utilising the electrospinning method to improve the ionic conductivity of SPEs.

Organic–inorganic composite polymer electrolyte based on PEO–LiClO4 and nano-Al2O3 filler for lithium polymer batteries: Dielectric and transport properties

Nano-Al2O3 with an average size of 42nm was prepared by pyrolysis method. PEO–LiClO4 based composite polymer electrolyte was prepared using solution cast technique. The samples were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and infra red (FT-IR) techniques. Effect of nano-Al2O3 ceramic filler concentration on the composite structure and its electrical properties (DC-conductivity, AC-conductivity, dielectric constant, dielectric loss and impedance) at a frequency and temperature ranges of 0–105Hz and 293–323K, respectively was studied. Melting temperature (Tm) of PEO decreased with addition of both LiClO4 salt and nano-Al2O3 filler due to increasing the amorphous state of polymer. All composite samples showed an ionic conductivity with the highest value for the sample containing 1.25mol of nano-Al2O3. All results are correlated and discussed.

Effects of MnO2 nano-particles on the conductivity of PMMA-PEO-LiClO4-EC polymer electrolytes

Li-ion rechargeable batteries based on polymer electrolytes are of great interest for solid state electrochemical devices nowadays. Many studies have been carried out to improve the ionic conductivity of polymer electrolytes, which include polymer blending, incorporating plasticizers and filler additives in the electrolyte systems. This paper describes the effects of incorporating nano-sized MnO2 filler on the ionic conductivity enhancement of a plasticized polymer blend PMMA–PEO–LiClO4–EC electrolyte system. The maximum conductivity achieved is within the range of 10−3 S cm−1 by optimizing the composition of the polymers, salts, plasticizer, and filler. The temperature dependence of the polymer conductivity obeys the VTF relationship. DSC and XRD studies are carried out to clarify the complex formation between the polymers, salts, and plasticizer.

Physicochemical properties of poly(ethylene oxide)-based composite polymer electrolytes with a silane-modified mesoporous silica SBA-15

Mesoporous silica SBA-15 was surface-modified by γ-glycidoxypropyltrimethoxy silane (GPTMS), and novel poly(ethylene oxide) (PEO)-based composite polymer electrolytes (CPE) using the silane-modified SBA-15 (SBA-15-GPTMS) as filler were prepared and characterized. The results of the low-angle X-ray diffraction (XRD) patterns and Fourier-transform infrared (FT-IR) spectroscopy indicated that GPTMS has been successfully attached to the surface of SBA-15 with a high degree of mesoscopic hexagonal pore structure. The incorporation of SBA-15-GPTMS in the PEO–LiClO 4 matrix effectively reduced the PEO crystallinity and obviously improved the conductivity and electrochemical stability of the CPEs. The CPE with 10 wt.% SBA-15-GPTMS provided the highest conductivity among all the tested CPEs, about 2–3 orders of magnitude higher than that of the PEO–LiClO 4 matrix below the melting temperature of PEO. The reasons that the CPEs using SBA-15-GPTMS as filler showed higher conductivity than that with SBA-15 were discussed.

Preparation and electrochemical behaviors of polymeric composite electrolytes containing mesoporous silicate fillers

In the present study, poly(ethylene oxide) (PEO)-based polymeric composite electrolytes (PCEs) had been prepared by using a different content of mesoporous silicate MCM-41, in order to examine the filler addition effect on the microstructural and electrochemical properties. The interactions between MCM-41 and PEO matrix were studied by XRD, DSC, and SEM techniques. The electrochemical properties of the PCEs, such as ionic conductivity, its temperature dependence, and lithium transference number were investigated. MCM-41 could maintain the pore structure effectively, resulting in nanocomposites that were homogeneously complexed with the PEO chains. The PCEs with 8 wt.% MCM-41 showed the smallest crystallinity, 30.4%. Accordingly, those PCEs showed the highest ion conductivity, 1.2 × 10 −4 S/cm, a two-order-of-magnitude higher value than that of the pristine PEO–LiClO 4. This might have reflected decreased crystallinity and improved ion transport. Furthermore, those PCEs showed an increased Li ion transference number of ∼0.5. In conclusion, the filler addition could enhance the ionic conductivity and increase the Li ion transference number at the same time.

The effect of type of the inorganic filler and dopant salt concentration on the PEO–LiClO 4 based composite electrolyte–lithium electrode interfacial resistivity

In the present paper the effect of the type of inorganic filler on the composite polymeric electrolyte–lithium electrode interfacial behavior is analyzed. Studies are performed in the wide LiClO 4 concentration range using poly(ethylene oxide)dimethyl ether (PEODME) as an electrolyte matrix. It is demonstrated that both the formation and the growth of the resistive layers at the polymer electrolyte–lithium electrode interface are determined by the salt concentration range and depend also on the type of the filler used. It is demonstrated that for salt concentrations lower than 10 −3 mol kg −1 or higher than 1 mol kg −1 addition of filler results in the suppression of the growth of the resistance of the interfacial layer. This effect has been related to an increase in lithium cation transference number observed in these salt concentration ranges in composite electrolytes compared to the pure PEODME–LiClO 4 analogues. The effect of the filler on conductivity, microstructure and thermal characteristic of electrolytes studied is also discussed.

The effect of salt concentration on the PEO–LiClO 4–lithium electrode interfacial resistivity

In the present paper the effect of the salt concentration on the formation and growth of the resistive layers at the polymer electrolyte–lithium electrode interface is analyzed. The studies are performed for poly(ethylene oxide)dimethyl ether (PEODME) doped with LiClO 4 electrolytes. It is shown that the rate of growth of the resistivity of interfacial layers depends on the concentration of the added salt and increases as the salt concentration increases. We have related this effect to the decrease in the lithium cation transference number and the increase in the fraction of ionic aggregates occurring with an increase in the salt concentration in polymeric electrolytes. The observed phenomena seem to be important from the viewpoint of application of polymeric electrolytes in lithium or (and) lithium ion batteries.

Investigations on the enhancement mechanism of inorganic filler on ionic conductivity of PEO-based composite polymer electrolyte: The case of molecular sieves

Polarized optical microscopy (POM) and differential scanning calorimeter (DSC) techniques are used to study the effect of ZSM-5 molecular sieves on the crystallization mechanism of poly(ethylene oxide) (PEO) in composite polymer electrolyte. POM results show that ZSM-5 has great influence on both the nucleation stage and the growth stage of PEO spherulites. ZSM-5 particles can act as the nucleus of PEO spherulites and thus increase the amount of PEO spherulites. POM and DSC results show that ZSM-5 can restrain the recrystallize tendency of PEO chains through Lewis acid–base interactions and hence decrease the growth speed of PEO spherulites. Room temperature ionic conductivity of PEO–LiClO 4-based polymer electrolyte can be enhanced by more than two magnitudes during long time storage with the addition of ZSM-5.

Enhanced electrochemical properties of poly(ethylene oxide)-based composite polymer electrolyte with ordered mesoporous materials for lithium polymer battery

Ordered mesoporous materials (OMMs), due to its potential for advanced applications in separation technologies, catalysis, and nanoscience, have attracted much attention in the past decade. In this work, a novel PEO-based composite polymer electrolyte has been developed by using ordered mesoporous silica (OMS) as the filler. The interactions between OMS and PEO matrix are studied by XRD, DSC, and POM techniques in detail. The effects of OMS on the electrochemical properties of the PEO-based polymer electrolyte, such as ionic conductivity, lithium ion transference number, and electrochemical stability windows are studied by electrochemical impedance spectroscopy and steady-state current method. The experimental results show that the addition of OMS can enhance the ionic conductivity and increase the lithium ion transference number of PEO-based polymer electrolyte at the same time. The excellent performances such as high ionic conductivity, good mechanical stability, and broad electrochemical stability window suggest that PEO–LiClO 4/OMS composite polymer electrolyte can be used as candidate electrolyte material for lithium polymer batteries.

Enhanced electrochemical properties of PEO-based composite polymer electrolyte with shape-selective molecular sieves

ZSM-5 molecular sieves, usually known as shape-selective catalyst in a great deal of catalysis fields, due to its special pore size and two-dimensional interconnect channels. In this work, a novel PEO-based composite polymer electrolyte by using ZSM-5 as the filler has been developed. The interactions between ZSM-5 and PEO matrix are studied by DSC and SEM techniques. The effects of ZSM-5 on the electrochemical properties of the PEO-based electrolyte, such as ionic conductivity, lithium ion transference number, and interfacial stability with lithium electrode are studied by electrochemical impedance spectroscopy and steady-state current method. The experiment results show that ZSM-5 can enhance the ionic conductivity and increase the lithium ion transference number of PEO-based electrolyte more effectively comparing with traditional ceramic fillers such as SiO 2 and Al 2O 3, resulting from its special framework topology structure. The excellent performances such as high ionic conductivity, good compatibility with lithium metal electrode, and broad electrochemical stability window suggesting that PEO–LiClO 4/ZSM-5 composite polymer electrolyte can be used as candidate electrolyte materials for lithium polymer batteries.

Nanocomposite polymer electrolyte comprising PEO/LiClO 4 and solid super acid: effect of sulphated-zirconia on the crystallization kinetics of PEO

A novel PEO-based nanocomposite polymer electrolyte is prepared by using solid super acid sulphated-zirconia ( SO 4 2 − - ZrO 2 , SZ) as the filler. Polarized optical microscopy (POM) and differential scanning calorimeter (DSC) results show that part of SZ particles may act as the nucleus of PEO spherulites and thus increase the amount of PEO spherulites. On the other hand, other SZ particles, which do not act as the nucleus, can restrain the recrystallization tendency of PEO chains through Lewis acid–base interaction and hence decrease the growth speed of PEO spherulites. As a result, the PEO component in PEO–LiClO 4–SZ can maintain a high amorphous state for a long time. The room temperature ionic conductivity of PEO–LiClO 4–SZ is relative high and stable compared with pristine PEO–LiClO 4, indicating that it is promising for all solid-state rechargeable lithium ion batteries.

Novel composite polymer electrolyte comprising poly(ethylene oxide) and triblock copolymer/mesostructured silica hybrid used for lithium polymer battery

Ordered mesoporous materials, due to its potential applications in catalysis, separation technologies, and nano-science have attracted much attention in the past few years. In this work, a novel PEO-based composite polymer electrolyte by using organic–inorganic hybrid EO 20PO 70EO 20 @ mesoporous silica (P123 @ SBA-15) as the filler has been developed. The interactions between P123 @ SBA-15 hybrid and PEO chains are studied by X-ray diffraction (XRD), differential scanning calorimeter (DSC), and FT-IR techniques. The effects of P123 @ SBA-15 on the electrochemical properties of the PEO-based electrolyte, such as ionic conductivity, lithium ion transference number are studied by electrochemical ac impedance spectroscopy and steady-state current method. The experiment results show that P123 @ SBA-15 can enhance the ionic conductivity and increase the lithium ion transference number of PEO-based electrolyte, which are induced by the special topology structure of P123 in P123 @ SBA-15 hybrid, at the same time. The excellent lithium transport properties and broad electrochemical stability window suggesting that PEO–LiClO 4/P123 @ SBA-15 composite polymer electrolyte can be used as candidate electrolyte materials for lithium polymer batteries.

Composite polymer electrolyte doped with mesoporous silica SBA-15 for lithium polymer battery

SBA-15, due to its ordered mesoporous structure and potential for advanced applications in separation technologies, catalysis, and nanoscience, has attracted much attention in the past few years. In this work, a novel PEO-based composite polymer electrolyte has been developed by using SBA-15 as the filler. The interactions between SBA-15 and PEO matrix are studied by XRD, DSC, and FT-IR techniques in detail. The effects of SBA-15 on the electrochemical properties of the PEO-based polymer electrolyte, such as ionic conductivity, lithium ion transference number, and interfacial stability with lithium electrode, are studied by electrochemical impedance spectroscopy and steady-state current method. The experiment results show that the addition of SBA-15 can enhance the ionic conductivity and increase the lithium ion transference number of PEO-based polymer electrolyte at the same time. The excellent performances such as high mechanical stability, good compatibility with lithium metal electrode, and broad electrochemical stability window suggest that PEO–LiClO 4/SBA-15 composite polymer electrolyte can be used as candidate electrolyte material for lithium polymer batteries.

Conductivities and transport properties of microporous molecular sieves doped composite polymer electrolyte used for lithium polymer battery

Microporous molecular sieves (MMS), due to their potential for advanced applications in separation technologies, catalysis, and nanoscience, have attracted much attention in the past decades. In this work, a novel PEO-based all solid-state composite polymer electrolyte by using MMS as filler is developed. Thermal analysis and polarized optical microscopy results show that MMS can increase the amount of PEO spherulites and decrease their size, which is beneficial for decreasing the crystallinity of PEO. There exists a much more continuous amorphous phase of PEO in PEO–LiClO4/MMS compared with the continuous crystalline phase of PEO in pristine PEO–LiClO4, which results in enhancement of ionic conductivity. The excellent lithium transporting properties combined with high decomposition voltage ensures the use of PEO–LiClO4/MMS as a candidate electrolyte material for all solid-state rechargeable lithium polymer batteries.

Enhanced lithium ion transference number and ionic conductivity of composite polymer electrolyte doped with organic–inorganic hybrid P123@SBA-15

A novel Poly(ethylene oxide)-based composite polymer electrolyte by using organic–inorganic hybrid EO 20PO 70EO 20@mesoporous silica (P123@SBA-15) as the filler has been developed. The experiment results show that P123@SBA-15 can enhance the lithium ion transference number and ionic conductivity of the electrolyte, which are induced by the special topology structure of P123 in P123@SBA-15 hybrid, at the same time. The excellent lithium ion transporting properties suggesting that the composite polymer electrolyte PEO–LiClO 4/P123@SBA-15 can be used as candidate electrolyte material for lithium polymer batteries.

Nanocomposite polymer electrolyte based on Poly(ethylene oxide) and solid super acid for lithium polymer battery

This Letter reports a novel PEO-based nanocomposite polymer electrolyte by using solid super acid SO 4 2−/ZrO 2 as filler. XRD, DSC, and FT-IR results prove the strong Lewis acid–base interactions between SO 4 2−/ZrO 2 and PEO chains. The addition of SO 4 2−/ZrO 2 can enhance the ionic conductivity and the lithium ion transference number of the electrolyte. The highest room temperature ionic conductivity of 2.1 × 10 −5 S cm −1 is obtained for the sample PEO 12–LiClO 4–7%SO 4 2−/ZrO 2. The excellent performances such as good compatibility with lithium electrode, and broad electrochemical stability window suggest that PEO–LiClO 4–SO 4 2−/ZrO 2 nanocomposite electrolyte can be used as electrolyte materials for lithium polymer batteries.

Polyether-grafted SnO2 nanoparticles designed for solid polymer electrolytes with long-term stabilityElectronic supplementary information (ESI) available: XPS results and in situ IR spectra. See http://www.rsc.org/suppdata/jm/b4/b405179c/

Polyether-grafted SnO2 nanoparticles are prepared through a hydrothermal method and exchange reactions. X-ray diffraction (XRD) and transmission electron microscopic (TEM) results illustrate that these nanoparticles are uniform, mono-dispersed and about 3 nm in diameter, while thermo-gravimetric and differential thermal analyses (TG-DTA) and infrared (IR) data prove that poly(ethylene glycol methyl ether) (PEGME) groups are bound tightly on SnO2 surfaces. The composites of such PEGME-SnO2 nanoparticles and LiClO4 exhibit ionic conductivity over 10−5 S cm−1, and the PEGME–SnO2–LiClO4 composites act as the main conductive component when PEGME–SnO2 fillers are incorporated in the prototypical PEO–LiClO4 films. The PEO–(PEGME–SnO2)–LiClO4 films exhibit improved conductivities with long-term stability, enhanced Li+ transference numbers and better mechanical properties.

Improvement of room-temperature conductivity and thermal stability of PEO–LiClO 4 systems by addition of a small proportion of polyethylenimine

Thermal behavior was examined using DSC and TG for the samples prepared by dissolving LiClO 4 in several polyoxyethylene/polyethylenimine (PEO/PEI) blends (7/3–9.5/0.5 by repeat units) along with their lithium ion conductivity. Concerning the matrix polymers, while the pristine PEO and PEI began to thermally decompose at 185 and 230 °C, respectively, the (8/2) PEO/PEI blend had lost only 6.5% of its weight before 300 °C was reached. Dissolution of LiClO 4 made the systems thermally even more robust: [(8/2) PEO/PEI] 10–LiClO 4 suffered practically no weight loss below 300 °C. So far [(8/2) PEO/PEI] 10–LiClO 4 has been our best-behaving SPE ( σ=2.2×10 −4 S cm −1 at 77 °C and 2.5×10 −6 S cm −1 at 30 °C): it is less conductive than a previously reported PEO 12–LiClO 4 by a factor of 2.2 at 77 °C, but its conductivity drop due to the matrix crystallization below 65 °C is considerably milder and the conductivity at 30 °C was ca. 100 times higher than the plain PEO–LiClO 4 systems. A significant effect of the residual methanol on the ionic conductivity of our [(8/2) PEO/PEI] 10–LiClO 4 samples was recognized, which necessitated our previously reported log σ vs. 1000/ T curve to be corrected downward by ca. half an order of magnitude.