Polymer Electrolyte Research Articles

Advanced Ru/Ti4O7 catalyst for Tolerating CO and H2S poisoning to hydrogen oxidation reaction

CO and H2S poisoning of Pt-based catalysts for hydrogen oxidation reaction (HOR) stands as one of the long-standing hindrances to the widespread commercialization of proton exchange membrane fuel cells. In this paper, a Ru/Ti4O7 catalyst is successfully synthesized by the microwave-thermal method. This Ru/Ti4O7 catalyst shows a much higher noble metal mass activity than those of commercial PtRu/C and conventional Ru/C catalysts. The performance of the Ru/Ti4O7 catalyst under the exist of CO or H2S shows insignificant current decay, which is far superior to commercial PtRu/C and Pt/C catalysts. In this Ru/Ti4O7 catalyst, the electron transfer between Ru and Ti to form d-p orbital hybridization is considered to be responsible for the favorable catalytic HOR performance and the corresponding CO and H2S tolerance. The interaction mechanism formed by electron transfer may open a promising way for the subsequent development of anti-poisoning catalysts for PEM fuel cell hydrogen oxidation reaction.

TiO2 nanolayer coated carbon support for highly durable high-temperature polymer electrolyte membrane fuel cell cathode

Carbon corrosion of Pt/C electrocatalyst in the cathode is a critical issue for the practical application of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). Herein, we introduce a nanolayer composed of TiO2 nanoparticles between Pt and carbon support, which not only protects the carbon from corrosion but also forms a strong metal-support interaction between Pt and TiO2. The Pt nanoparticles are uniformly dispersed on the prepared C@TiO2 support (mean size: 2.27 nm). After potential sweeping for 5000 cycles in the acid solution, the electrochemical surface area loss of the homemade Pt/C@TiO2 is 10.9%, which is approximately half of that of commercial Pt/C (19.1%). In the practical HT-PEMFC single cell, Pt/C@TiO2 exhibits superior durability than Pt/C as well. After the accelerated durability test, the maximum power density of Pt/C@TiO2-MEA decreases by 8.6%, which is significantly lower than that of Pt/C-MEA (23.9%), suggesting a great potential application of Pt/C@TiO2 in HT-PEMFCs.

Poly(phenylene oxide) cross-linked with polybenzimidazole for the applications of high-temperature proton-exchange membrane fuel cells

A series of imidazolium-functionalized poly(phenylene oxide) (QPPO) cross-linked with polybenzimidazole (PBI) (cQPPOx-PBI) membranes were prepared. Compared to the pure PBI membrane without a cross-linked structure nor imidazolium groups, the cQPPOx-PBI membranes showed enhanced toughness, phosphoric acid (PA) retention, and chemical stability. The cQPPOx-PBI membranes showed a enhanced PA uptake than that of PBI membranes, and the cQPPO35-PBI membrane achieves a high conductivity of 139 mS cm−1 at 160 °C, which is much higher than that of PBI membrane under the same conditions (26 mS cm−1). The performance of the single fuel cell assembled with the obtained membranes showed a similar trend as their conductivity, and the cell with cQPPO35-PBI showed a maximum power density of 344 mW cm−2 at 140 °C, while the value for PBI membrane was only 175 mW cm−2 under the same conditions. Herein, a straightforward method was developed for introducing imidazolium groups and cross-linked structures, which can be employed to prepare PEMs with enhanced performance for HT-PEMFCs application.

Coordination polymer-reinforced composite polymer electrolyte for all-solid-state Li-metal batteries

Composite polymer electrolytes (CPEs) have garnered significant interest due to their lightweight, flexible, and suitability for large-scale processing. However, current CPEs still face challenges such as unsatisfactory ionic conductivity (σ), low Li+ transference number (t+), and poor interfacial stability. This study presents the synthesis of a coordination polymer by coordinating Co2+ with terpyridine-end-capped polyethylene glycol (Co(tpy)-PEG). The resulting Co(tpy)-PEG-reinforced PEO-based CPE exhibits exceptional properties, including a high σ of 0.22 mS cm−1, large t+ of 0.75, and superior durability in both Li|Li (1400 h at 0.2 mA cm−2) and Li|LiFePO4 cells (70 % capacity retention after 1000 cycles at 1C) at 60 °C, comparable to the best available CPEs. The incorporation of Co(tpy)-PEG filler plays a vital role in enhancing the σ by disrupting the PEO crystallinity and creating additional Li+ conducting pathways. Additionally, it can free Li+ to increase t+ through Lewis acid-base interactions between Co2+ and TFSI−/O atoms, as well as NO3− and Li+. Furthermore, Co(tpy)-PEG facilitates the formation of a stable multicomponent solid electrolyte interphase containing beneficial Li2Sx, LiF, and Li3N. This work introduces a promising strategy for designing and preparing multifunctional fillers capable of simultaneously reinforcing the σ, t+, and interfacial stability of CPEs.

Lignin Derived Ultra-Thin All-Solid Polymer Electrolytes with Three dimensional Single-ion Nanofiber Ionic Bridge Framework for High Performance Lithium Batteries.

Solid-state lithium batteries are promising candidates for the next generation high security and high performance batteries. Here, the lignin derived ultra-thin all-solid composite polymer electrolytes (CPEs) with a thickness of only 13.2μm, which possessed three dimensional nanofiber ionic bridge networks composed of single-ion lignin based lithium (L-Li) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as the framework, and poly(ethylene oxide)/lithium bis(trifluoromethanesulfonyl)imide (PEO/LiTFSI) as the filler, was obtained through electrospinning/spraying and hot-pressing process. The obtained CPE presented high ionic conductivity of 1.3×10-4 S cm-1, excellent oxidative stability of 4.7V, and satisfactory tensile strength of up to 9.30MPa. The Li||Li symmetric cell assembled with the CPE can stably cycle more than 6500h under 0.5mA cm-2 with little Li dendrites growth. Moreover, the assembled Li||CPE||LiFePO4 cells can stably cycle over 700 cycles at 0.2 C with a super high initial discharge capacity of 158.5 mAh g-1 at room temperature, and a favorable capacity of 123 mAh g-1 at -20°C for 250 cycles, and Li||CPE|| NCM can also stably cycle more than 70 cycles with a favorable discharge capacity of 132.4 mAh g-1 at 0.2 C and 30°C. The excellent electrochemical performance was mainly attributed to the reason that the nanofiber ionic bridge network can afford uniformly dispersed single-ion L-Li through electrospinning, which synergized with the LiTFSI well dispersed in PEO to form abundant and efficient three dimensional Li+ transfer channels. Furthermore, the ultra-thin CPE can be compactly attached to the lithium anode, and provided a shorter ion transmission distance between the electrodes, inducing uniform deposition of Li+ at the interface, and inhibiting the lithium dendrites. This work provided a promising strategy to achieve ultra-thin biobased electrolytes with high tensile strength and electrochemical performance for solid-state LIBs. This article is protected by copyright. All rights reserved.

Thermoeconomic Analysis of an Innovative Integrated System for Cogeneration of Liquid Hydrogen and Biomethane by a Cryogenic-Based Biogas Upgrading Cycle and Polymer Electrolyte Membrane Electrolysis

Thermoeconomic Analysis of an Innovative Integrated System for Cogeneration of Liquid Hydrogen and Biomethane by a Cryogenic-Based Biogas Upgrading Cycle and Polymer Electrolyte Membrane Electrolysis

Fundamental Picture of the Conduction Mechanism in Solid-State Polymer Electrolytes Revealed by Terahertz Spectroscopy

Fundamental Picture of the Conduction Mechanism in Solid-State Polymer Electrolytes Revealed by Terahertz Spectroscopy

Effects of Humidity and Produced Water on Specific Adsorption of High Oxygen Permeability Ionomers Composed Entirely of Cyclic Monomers on Cathode Performance for Polymer Electrolyte Fuel Cells

Effects of Humidity and Produced Water on Specific Adsorption of High Oxygen Permeability Ionomers Composed Entirely of Cyclic Monomers on Cathode Performance for Polymer Electrolyte Fuel Cells

Flexible High Lithium-Ion Conducting PEO-Based Solid Polymer Electrolyte with Liquid Plasticizers for High Performance Solid-State Lithium Batteries.

Lithium-ion secondary batteries (LIB) with high energy density have attracted much attention for electric vehicle (EV) applications. However, LIBs have a safety problem because these batteries contain a flammable organic electrolyte. As such, all-solid secondary batteries that are not flammable have been extensively reported recently. In this study, we have focused on polymer electrolytes, which is flexible and is expected to address the safety problem. However, the conventional polymer electrolytes have low electrial conductivity at room temperature. Various attempts have been made to solve this problem, such as the addition of inorganic fillers and ionic liquids; however, these composite polymer electrolytes have not yet reached a practical level of lithium-ion conductivity. In this study, high electrical conductivity and lithium dendrite formation-free PEO based composite electrolytes are developed with both a filler of Li6,4La3Zr1.4Ta0.6O12 and liquid plasticizers of tetraethylene glycol dimethyl ether and 1,2 dimethoxyethane. The proposed flexible polymer electrolyte shows a high electrical conduciviy of 6.01×10-4 S cm-1 at 25 °C.

Asymmetric Solid-State Lithium-Metal-Battery Electrolytes Featuring Na Superionic Conductor-Type Ceramic and Garnet-Type Ceramic Filled Composite Polymer

Abstract In this study, Li1.3Al0.3Ti1.7(PO4)3 (LATP)-based lithium metal battery (LMB) cells are prepared using two different protection layers against Li metal: a solid polymer electrolyte (SPE) containing polyethylene oxide and lithium bis(fluorosulfonyl)imide (LiTFSI), and a composite polymer electrolyte (CPE) filled with a 14 wt% Li6.4La3Zr1.4Ta0.6O12 (LLZTO). The CPE-containing symmetric cell exhibits a smaller overvoltage than that of its SPE-containing counterpart, which is maintained for ~1000 h at 0.1 mA·cm-2 at 60 °C, owing to enhanced Li-ion transport in the CPE and at the LATP–CPE interface as well as the uniform Li deposition induced by the CPE with a higher Li+ transference number. Post-material analyses reveal that the CPE imparts long-term (~1000 h) protection to the LATP against Li metal, whereas the SPE is effective over a shorter period (~100 h). The CPE-based full cell exhibits a higher capacity (~141 mAh·g-1; with a LiFePO4) and capacity retention (~95%) than those of the SPE-based full cell (~130 mAh·g-1 and ~ 55%, respectively), for 310 cycles at 60 °C. This study recommends utilizing asymmetric solid electrolytes containing a ceramic (LATP at the cathode) and composite polymer (PEO + LLZTO at the anode) to improve cyclability and suppress Li dendrite growth in solid-state LMBs.

Performance Degradation Trend Prediction of Proton Exchange Membrane Fuel Cell Based on GA-TCN

Abstract To improve the prediction accuracy of the performance degradation trend of proton exchange membrane fuel cell (PEMFC), this paper proposes a temporal convolutional network (TCN) model based on genetic algorithm (GA) optimization to predict the performance degradation trend of PEMFC. Firstly, variational mode decomposition (VMD) and wavelet threshold denoising (WTD) algorithms are used to denoise the original data. Then the hyperparameters of the TCN model are optimized by GA, and the GA-TCN model for predicting the performance degradation trend of PEMFC is constructed. Finally, this paper uses the PEMFC stack degradation experimental dataset disclosed in the IEEE PHM 2014 Data Challenge to verify, and compares the proposed model with the backpropagation neural networks model (BP), the long short-term memory model (LSTM) and the classical temporal convolutional network model. The results show that the proposed method has the highest performance degradation trend prediction accuracy. In particular, when the training dataset accounts for 30%, i.e. the training samples are small, the root mean square error (RMSE) and mean absolute error (MAE) of the GA-TCN model are 0.004726 and 0.003119, respectively, which are 14.48% and 20.05% lower than that of the classical TCN model. Consequently, this methodology can forecast the degradation trend of PEMFC with high accuracy.

Phytic Acid Customized Hydrogel Polymer Electrolyte and Prussian Blue Analogue Cathode Material for Rechargeable Zinc Metal Hydrogel Batteries.

Zinc anode deterioration in aqueous electrolytes, and Zn dendrite growth is a major concern in the operation of aqueous rechargeable Zn metal batteries (AZMBs). To tackle this,the replacement of aqueous electrolytes with a zinc hydrogel polymer electrolyte (ZHPE) is presented in this study. This method involves structural modifications of the ZHPE by phytic acid through an ultraviolet (UV) light-induced photopolymerization process. The high membrane flexibility, high ionic conductivity (0.085Scm-1), improved zinc corrosion overpotential, and enhanced electrochemical stability value of ≈2.3V versus Zn|Zn2+ show the great potential of ZHPE as an ideal gel electrolyte for rechargeable zinc metal hydrogel batteries (ZMHBs). This is the first time that the dominating effect of chelation of phytic acid with M2+ center over H-bonding with water is described to tune the gel electrolyte properties for battery applications. The ZHPE shows ultra-high stability over 360h with a capacity of 0.50mAhcm-2 with dendrite-free plating/stripping in Zn||Zn symmetric cell. The fabrication of the ZMHB with a high-voltage zinc hexacyanoferrate (ZHF) cathode shows a high-average voltage of ≈1.6V and a comparable capacity output of 63mAhg-1 at 0.10Ag-1 of the current rate validating the potential application of ZHPE.

Effect of NASCION‐Type ceramic dispersion in PAN/PVA‐based blend polymer electrolyte: A structural, thermal, and electrical study

AbstractSolid flexible separators having adequate ion conductivity at ambient temperature along with good thermal and voltage stability are potential candidates for separators in all solid‐state ion batteries. In the present work, zirconium and niobium‐doped Li1.3Al0.3Ti1.7 (PO4)3 ceramic particles have been incorporated into a polyvinyl alcohol (PVA) and polyacrylonitrile (PAN)‐based blend that served as a flexible matrix to create a flexible polymer–ceramic framework and have been examined for conductivity, dielectric properties, voltage stability, thermal stability, and electrochemical performance. The flexible polymer–ceramic framework shows high thermal stability, improved conductivity, and a high‐voltage window. Optimized dc conductivity of 9.8 × 10−5 S cm−1 has been observed among all investigated samples, with an improved voltage stability of 4.94 V. Further, the Trukhan model has been used to understand the effect of filler loading on ion migration properties. The optimized solid polymer electrolyte (SPE) shows improved ion mobility (μ) of 5.13 × 10−2 cm2 V−1 s, number density (n) = 2.39 × 1015 cm3, and diffusion coefficient (D) of 2.09 × 10−3 cm2 s−1. It also shows a very high specific capacitance of ~10−4 Fg−1, excellent cycling stability, and 93.75% capacity retention after 100 cycles.

Corrosion behavior and surface structure analysis of pure aluminum immersed in fluoride‐sulfate solutions simulating polymer electrolyte membrane fuel cell‐produced water

AbstractBipolar plates are the key component in polymer electrolyte membrane fuel cells (PEMFCs), which ensure the low cost of the fuel cell stack and furnish some of the important applications such as distributing the reactant gases, conducting the electrons, and removing the waste heat in PEMFCs. Thus, metallic bipolar plates (BPs), such as aluminum (Al), have attracted immense consideration and afford better performance in different machine‐driven applications and mass manufacturing opportunities. In order to increase the corrosion resistance of Al BPs, several methods are used and conducted by scientists. The corrosion behavior and surface structure analysis of pure Al were studied through the immersion process in fluoride‐sulfate solutions, assuming its use as BPs in PEMFC‐produced water. The open cell voltage, interfacial contact resistance, and polarization tests and the fuel cell operations were performed to evaluate cell voltage, current density, corrosion resistance, and the effect of fluoride and sulfate ions on the BPs in PEMFC. The hydrophobicity character of the surface of Al BPs was observed by the measurement of the wettability test. The atomic force microscopy images were taken to study the surface roughness, which was correlated with the corrosion rates of Al BPs. In addition, the amount of corrosion was calculated after 24–120 h of immersion in fluoride‐sulfate solutions. The scanning electron microscopy, transmission electron microscopy, and energy‐dispersive X‐ray spectroscopy data were analyzed to investigate the surface structure, morphology, and elemental analyses. Thus, the results found in this study revealed that Al‐based materials can be suitable for BPs in PEMFCs. Furthermore, it is noticed that the amount of corrosion was influenced by the presence of even a very small amount of fluoride ions present in the PEMFC environment, while it was suppressed efficiently by sulfate ions.

Structured mesh material with gradient surface wettability for high-power-density proton exchange membrane fuel cells

ABSTRACT A compact cell structure is highly desirable for next-generation high-power-density proton exchange membrane (PEM) fuel cell (>9.0 kW L−1). A novel integrated bipolar plate (BP) – gas diffusion layer (GDL) structure utilizing porous material is a promising configuration, which not only improves output power due to the reduced transport resistance but also reduces cell thickness. Herein, we propose a structured mesh material with gradient surface wettability for this cell structure, which is characterized by an ordered skeleton in the three-dimensional (3D) space with high structure design flexibility. It is experimentally found that the structured mesh material shows higher performance than serpentine and parallel flow fields. Meanwhile, 3D modeling work on an automobile fuel cell (cell area: 245.76 cm2) with the distribution zones of dot matrix structure for hydrogen, air and coolant flow, is conducted, and it is found that the structured mesh material effectively decreases the concentration and electric ohmic losses in comparison with the traditional “BP/flow field + GDL” structure, improving power density with uniform distribution characteristics. Moreover, the gradient wettability on the mesh surface helps promote the water detach the GDL and hold the residual liquid water in the top region, optimizing the water management.

The difference of the ionomer–catalyst interfaces for poly(aryl piperidinium) hydroxide exchange membrane fuel cells and proton exchange membrane fuel cells

The difference of the ionomer–catalyst interfaces for poly(aryl piperidinium) hydroxide exchange membrane fuel cells and proton exchange membrane fuel cells

A review of advancements in commercial and non-commercial Nafion-based proton exchange membranes for direct methanol fuel cells

A review of advancements in commercial and non-commercial Nafion-based proton exchange membranes for direct methanol fuel cells

Preparation and opto-electrical characterization of poly(ethylene oxide) based polymer blends for electrochemical applications

Solid polymer electrolyte blends with varied compositions of poly(ethylene oxide) (PEO)/carboxymethyl cellulose (Na-CMC) in 10/90, 50/50, and 90/10 compositions have been successfully prepared by means of the solution cast technique at room temperature. The modification of the structural, optical, and electrical properties of the prepared blend samples was studied by employing XRD, FTIR, UV-Vis, and electrical impedance spectroscopy methods. X-ray diffraction studies revealed that the crystalline nature gradually transforms into amorphous as the Na-CMC content increases in the sample. The variation of bands noticed in the Fourier transform infrared spectroscope characteristic spectrum of the blends reveals the formation of complexes between the individual polymers. The analysis of optical properties using a UV-Vis spectrometer in the wavelength range of 900–1100nm, shows a gradual decrease in the optical indirect energy band gap with an increase in Na-CMC content in the blend. The study of the electrical properties of the blend carried out in the frequency range 50 Hz–1MHz and temperature range 303K–338K, using an electrical impedance analyzer reveals that, the dielectric constant and loss decrease with the rise in frequency, exhibiting the usual behavior of the polymers. AC conductivity is found to increase with an increase in temperature. The highest value of ionic conductivity is found to be 6.06 × 10−3Scm−1 for the blend with a 10/90 composition.

Constructing Robust LiF‐Enriched Interfaces in High‐Voltage Solid‐State Lithium Batteries Utilizing Tailored Oriented Ceramic Fiber Electrolytes

AbstractThe pursuit of high‐performance energy storage devices has fueled significant advancements in the all‐solid‐state lithium batteries (ASSLBs). One of the strategies to enhance the performance of ASSLBs, especially concerning high‐voltage cathodes, is optimizing the structure of composite polymer electrolytes (CPEs). This study fabricates a high‐oriented framework of Li6.4La3Zr2Al0.2O12 (o‐LLZO) ceramic nanofibers, meticulously addressing challenges in both the Li metal anode and the high‐voltage LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode. The as‐constructed electrolyte features a highly efficient Li+ transport and robust mechanical network, enhancing both electron and ion transport, ensuring uniform current density distribution, and stress distribution, and effectively suppressing Li dendrite growth. Remarkably, the Li symmetric cells exhibit outstanding long‐term lifespan of 9800 h at 0.1 mA cm−2 and operate effectively over 800 h even at 1.0 mA cm−2 under 30 °C. The CPEs design results from the formation of a gradient LiF‐riched SEI and CEI film at the Li/electrolyte/NCM811 dual interfaces, enhancing ion conduction and maintaining electrode integrity. The coin‐cells and pouch cells demonstrate prolonged cycling stability and superior capacity retention. This study sets a notable precedent in advancing high‐energy ASSLBs.

Thiol‐Ene Photo Crosslinked PUA‐PUMA‐Based Flexible Gel Polymer Electrolyte for Lithium‐Ion Batteries

AbstractCrosslinked polymer films, formed via sol–gel and UV photocrosslinking, serve as gel polymer electrolytes (GPEs) in lithium‐ion batteries. Combining polyurethane acrylate (PUA), polyurethane methacrylate (PUMA), pentaerythritol tetrakis (3‐mercaptopropionate) (PETMP), and 3‐mercaptopropyl trimetoxysilane (MPTMS) yields flexible membranes, enhancing stability and liquid electrolyte compatibility. The resulting GPE displays higher ionic conductivity (1.46 × 10−3 S cm−1) than Celgrad2500, with PUA‐PUMA's hydrophilicity and PETMP's SH groups preventing leakage. GPPF1, the developed GPE, offers improved ionic conductivity, a stable electrochemical window up to 3.8 V, and heightened safety for versatile energy storage systems.