As-prepared Gel Polymer Electrolytes Research Articles

Preparation and electrochemical properties of gel polymer electrolytes using triethylene glycol diacetate-2-propenoic acid butyl ester copolymer for high energy density lithium-ion batteries

Gel polymer electrolytes (GPE) composed of triethylene glycol diacetate (TEGDA)–2-propenoic acid butyl ester (BA) copolymer and commercial used liquid organic electrolyte are prepared via in situ polymerization. The ionic conductivity of the as-prepared GPE can reach 5.5 × 10−3 S cm−1 with 6 wt% monomers and 94 wt% liquid electrolyte at 25 °C. Additionally, the temperature dependence of the ionic conductivity is consistent with an Arrhenius temperature behavior in a temperature range of 20–90 °C. Furthermore, the electrochemical stability window of the GPE is 5 V at 25 °C. A Li|GPE|(Li[Li1/6Ni1/4Mn7/12]O2) cell has been fabricated, which shows good charge–discharge properties and stable cycle performance compared to liquid electrolyte under the same test conditions.

PREPARATION AND CHARACTERISTICS OF NOVEL HYPERBRANCHED PEU-BASED GEL POLYMER ELECTROLYTES

Gel polymer electrolytes (GPEs) based on hyperbranched poly (ether urethane) (PHEU) were prepared from the reaction of the hyperbranched polyether (PHEMO) with different diisocyanates in liquid electrolyte. The ionic conductivities and transference number of the GPEs were investigated by alternating current (AC) impedance and multi-potential steps. It is found that the ionic conductivities of GPEs were influenced by diisocyanate structure, lithium salt concentration and addition amount of liquid electrolyte. Sample PUM-0.5M-80% originated from 4, 4-diphenylmethane diisocyanate (MDI) as the hard segment shows the highest ionic conductivity of 2.41×10-3 Scm-1 at ambient temperature. The lithium ion transference number is 0.7. In addition, small molecules of liquid electrolyte were perfectly entrapped by polymer matrix, and liquid leakage in lithium ion battery was avoided. 5 . The hard segment provides good mechanical strength, while the soft segment improves the ionic conductivity. The rubbery soft segments can dissolve alkali metal salts, and help achieving high ion mobility, which originates from the interaction of the ether oxygen with the alkali metal ions. In the previous report 6 , the hyperbranched polyether (PHEMO) without stiff groups is selected as soft segment, as well as its amorphous state inherently derived from the hyperbranched molecular structure. Therefore, PHEMO is expected to improve the ionic conductivity of polymer electrolyte 7 . Due to their good mechanical properties, diisocyanates are chosen to act as hard segment domains contributing to the dimensional stability of the polymer electrolytes 8 . In this paper, GPEs based on PHEU were prepared with hyperbranched polyether (PHEMO) and diisocyanates in liquid electrolyte. Diisocyanates with different structures, such as aliphatic isocyanates of hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), or aromatic isocyanates of 4, 4-diphenylmethane diisocyanate (MDI) and 2, 4-tolune diisocyanate (TDI) were served as hard segments, respectively. The effects of diisocyanate structure, lithium salt concentration and addition amount of electrolyte on the ionic conductivities of the as-prepared GPEs were discussed and compared.

Influence of polymer concentration and dyes on photovoltaic performance of dye-sensitized solar cell with P(VdF-HFP)-based gel polymer electrolyte

A series of gel polymer electrolytes (GPEs) is synthesized using Poly(vinylidenefluoride-hexafluoropropylene) P(VdF-HFP) as the host matrix and propylene carbonate (PC)–diethyl carbonate (DEC) as plasticizers to fabricate dye-sensitized solar cells. Equal amounts of PC and DEC are used to comprehend high dielectric constant and low viscosity of the electrolyte. The as-prepared GPEs are characterized by XRD, FTIR and SEM. Their thermal properties and ionic conductivities are investigated by TGA/DSC analyses and AC impedance measurements, respectively. The optimized gel polymer electrolyte gives a maximum ionic conductivity of 5.25 × 10 −3 S cm −1 at room temperature. The formation of porous structure in the electrolyte film supports the entrapment of large volumes of liquid electrolyte inside its cavities. The role of N3 and N719 dyes are also investigated for better photovoltaic performance of DSSC. The overall light-to-electrical-energy conversion efficiencies of 3.95% and 4.41% are obtained for N3 and N719 dyes, respectively, under 100 mW cm −2 irradiation, which are comparable to those obtained from the corresponding liquid electrolyte cell.

Preparation of a microporous polymer electrolyte based on poly(vinyl chloride)/poly(acrylonitrile-butyl acrylate) blend for Li-ion batteries

Poly(acrylonitrile- co-butyl acrylate) (P(AN- co-BuA))/poly(vinyl chloride) (PVC) blend-based gel polymer electrolyte (BGPE) was prepared for lithium-ion batteries. The P(AN- co-BuA)/PVC BGPE consists of an electrolyte-rich phase, which is mainly composed of P(AN- co-BuA) and liquid electrolyte, acting as a conducting channel and a PVC-rich phase that provides mechanical strength. The dual phase was just simply developed by the difference of miscibility properties in solvent, PC, between P(AN- co-BuA) and PVC. The mechanical strength of this new blend electrolyte was found to be much higher, with a fracture stress as high as 29 MPa in dry membrane and 21 MPa in gel state, than that of a previously reported P(AN- co-BuA)-based gel polymer electrolyte. The blended gel polymer electrolyte showed ionic conductivity of higher than 1.5 × 10 −3 S cm −1 and electrochemical stability up to at least 4.8 V. The results showed that the as-prepared gel polymer electrolytes were promising materials for lithium-ion batteries.

Preparation of poly(acrylonitrile–butyl acrylate) gel electrolyte for lithium-ion batteries

Poly(acrylonitrile–butyl acrylate) gel polymer electrolyte was prepared for lithium ion batteries. The preparation started with synthesis of poly(acrylonitrile–butyl acrylate) by radical emulsion polymerization, followed by phase inversion to produce microporous membrane. Then, the microporous gel polymer electrolytes (MGPEs) was prepared with the microporous membrane and LiPF 6 in ethylene carbonate/diethyl carbonate. The dry microporous membrane showed a fracture strength as high as 18.98 MPa. As-prepared gel polymer electrolytes presented ionic conductivity in excess of 3.0 × 10 −3 S cm −1 at ambient temperature and a decomposition voltage over 6.6 V. The results showed that the as-prepared gel polymer electrolytes were promising materials for Li-ion batteries.