Innovative polycarbonates for lithium conducting polymer electrolytes

205 p.The highly qualified life, demanded by the society of the 21st century, requires constant scientific and technological developments. Energy is the essential ingredient for the economic and social development. In order to provide, clean energy, safe energy storage system has to be developed. The continuous research on polymer electrolytes will lead us into a promising energy storage system. Up to now, poly(ethylene oxide) (PEO) has been extensively explored polymer matrix in solid polymer electrolytes for lithium batteries. However, recently, polycarbonate-solid polymer electrolytes show considerable enhancements respect to PEO-solid polymer electrolytes, such as improved lithium conductivity and electrochemical stability. The main objective of this thesis is to evaluate and compare new polycarbonates¿ structures as SPEs in lithium batteries. For this purpose, the versatile and simple polycondensation technique was chosen as synthetic tool to develop polycarbonates. This synthetic method allowed to easily change the functionality of the diol and the properties of the polycarbonates, and therefore, to analyze the consequences in polymer electrolytes.Université de Pau et des Pays de l'Adour Polymat JPREM: Institut des sciences analytiques et de physics-chimie pour l'environnement et les matériau

Innovative polycarbonates for lithium conducting polymer electrolytes

205 p.The highly qualified life, demanded by the society of the 21st century, requires constant scientific and technological developments. Energy is the essential ingredient for the economic and social development. In order to provide, clean energy, safe energy storage system has to be developed. The continuous research on polymer electrolytes will lead us into a promising energy storage system. Up to now, poly(ethylene oxide) (PEO) has been extensively explored polymer matrix in solid polymer electrolytes for lithium batteries. However, recently, polycarbonate-solid polymer electrolytes show considerable enhancements respect to PEO-solid polymer electrolytes, such as improved lithium conductivity and electrochemical stability. The main objective of this thesis is to evaluate and compare new polycarbonates¿ structures as SPEs in lithium batteries. For this purpose, the versatile and simple polycondensation technique was chosen as synthetic tool to develop polycarbonates. This synthetic method allowed to easily change the functionality of the diol and the properties of the polycarbonates, and therefore, to analyze the consequences in polymer electrolytes.Université de Pau et des Pays de l'Adour Polymat JPREM: Institut des sciences analytiques et de physics-chimie pour l'environnement et les matériau

Single-ion conducting poly(ethylene oxide carbonate) as solid polymer electrolyte for lithium batteries

Unformatted postprintSingle-ion conducting polymer electrolytes (SIPE) have attracted a lot of interest for application in high energy density lithium metal batteries. SIPEs possess lithium transport numbers close to unity, which does not provoke concentration gradients and holds the promise of limiting lithium dendrite formation. In this article, we have optimized a single-ion polymer incorporating the most successful chemical units in polymer electrolytes, such as ethylene oxide, carbonate and a lithium sulfonimide. This single-ion poly(ethylene oxide carbonate) copolymer was synthesized by polycondensation between polyethylene glycol, dimethyl carbonate and a functional diol including the pendant sulfonamide anionic group and the lithium counter-cation. By playing with the monomer stoichiometry, the crystallinity and ionic conductivity were optimized. The best copolymer showed high ionic conductivity values of 1.2·10-4 S.cm-1 at 70 °C. Lithium interactions and mobility were studied by lithium pulsed field gradient, lithium diffusion, NMR relaxation time measurements and FTIR-ATR analysis. High lithium mobility is observed which is due to the weakly coordinating chemical environment in the polymer and also that the sulfonamide in the SIPE adopts to a greater extent the cis conformation, which is known to promote lithium mobility. Finally, the performance of the singe-ion conducting poly(ethylene oxide carbonate) was compared in lithium symmetric cells versus an analogous conventional salt in polymer electrolyte, showing improved performance in lithium plating and stripping.We are grateful to the financial support of the European Research Council by the Starting Grant Innovative Polymers for Energy Storage (iPes) 306250 and IONBIKE (H2020-MSCA-RISE-2018-823989), and by the Basque Government through ETORTEK Energigune 2013 and IT 999-16. Leire Meabe thanks Spanish Ministry of Education, Culture and Sport for the predoctoral FPU fellowship received to carry out this work. The authors thank for the technical and human support provided by SGIker of UPV/EHU for the NMR facilities of Gipuzkoa campus. The authors thank also Dr. Jose Ignacio Miranda (SGIker) for useful and essential support. Authors would like to thank the human support of Dr. Haijin Zhu and Dr. Luke O’Dell

Chemical Structure Drives Memory Effects in the Crystallization of Homopolymers

Unformatted post-print version of the accepted articleAlthough the study of melt memory has attracted much interest, the effect of polymer chemical structure on its origin has not been fully elucidated. In this work, we study melt memory effects by Differential Scanning Calorimetry employing a self-nucleation protocol. We use homologous series of homopolymers containing different polar groups and different number of methylene groups in their repeating units: polycarbonate, polyesters, polyethers and polyamides. We show that melt memory in homopolymers is generally controlled by the strength of the intermolecular interactions. The incorporation of methylene groups reduces melt memory effects by decreasing the strength of segmental chain interactions, which is reflected by the decrease in dipolar moments and solubility parameters. This work presents for the first time a unified view of the melt memory effects in different homopolymers.We acknowledge funding from MINECO MAT2017-83014-C2-1-P project, and from the Basque Government through grant IT1309-19. L. S acknowledges FPU predoctoral grant and the postdoctoral grant from Basque Governnment. We would also like to thank the financial support provided by the BIODEST project; this project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 778092

Solid–Solid Crystal Transitions (δ to α) in Poly(hexamethylene carbonate) and Poly(octamethylene carbonate)

Unformatted post-print version of the accepted articlePoly (hexamethylene carbonate) (PC6) and poly (octamethylene carbonate) (PC8) were studied under different crystallization conditions. Using differential scanning calorimetry (DSC), a new solid-solid transition, denoted α to δ transition, was detected at low temperatures (<RT) in both PC6 and PC8 samples. The α to δ transition was represented by exothermic (i.e., α to δ) (−6 °C (PC6) and −20 °C (PC8)) and endothermic peaks (i.e., δ to α) (15 °C (PC6) and 28 °C (PC8)), during cooling and heating DSC scans, respectively. Isothermal tests revealed that this solid-solid transition depends on the specific thermal history, since it is not observed at isothermal temperatures higher than room temperature. Still, it is detected in the subsequent cooling and heating scans. Wide-angle X-ray scattering (WAXS) and Fourier-transform infrared spectroscopy (FT-IR) experiments were performed at identical conditions to those by DSC. WAXS experiments showed lower d-spacings in the δ phase than in the α one, corresponding to a unit cell shrinkage, explained by a more efficient packing of the methylene groups in the δ phase. The δ phase is also characterized, according to FT-IR experiments, by more ordered conformation of the methylene groups (i.e., reflected in the appearance of a new absorption band) compared to the less ordered conformation in the α phase.This work is supported by the National Key R&D Program of China (2017YFE0117800) and the National Natural Science Foundation of China (51820105005, 21922308, and 52050410327). We would like to thank the financial support provided by the BIODEST project; this project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 778092. This work has also received funding from MINECO through project MAT2017-83014-C2-1-P and from Basque Government through grant IT1309-19. R.A.P.-C is supported by the China Postdoctoral Science Foundation (2020M670462). G.L. is grateful to the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Y201908). We also thanks to the BSRF (beamline 1W2A)

Using Successive Self-Nucleation and Annealing to Detect the Solid−Solid Transitions in Poly(hexamethylene carbonate) and Poly(octamethylene carbonate)

Unformatted post-print version of the accepted articleSolid-solid transitions in poly (hexamethylene carbonate) (PC6) and poly (octamethylene carbonate) (PC8), denoted δ to α transition, have been investigated, using self-nucleation and Successive Self-nucleation and Annealing (SSA) technique. The SSA protocol was performed in-situ for thermal (differential scanning calorimetry (DSC)), structural (Wide-angle X-ray Scattering (WAXS)), and conformational (Fourier-transformed Infrared Spectroscopy (FT-IR)) characterization. The final heating after SSA fractionation displayed an enhanced (compared to a standard second DSC heating scan) endothermic and unfractionated peak signal at low temperatures corresponding to the δ to α transition. The improved (i.e., higher enthalpy and temperature than in other crystallization conditions) δ to α transition signal is produced by annealing the thickest lamellae made up by α and β phase crystals after SSA treatment. As thicker lamellae are annealed, more significant changes are produced in the δ to α transition, demonstrating the transition dependence on crystal stability, thus, on the crystallization conditions. The ability of SSA to significantly enhance the observed solid-solid transitions makes it an ideal tool to detect and study this type of transitions. In-situ WAXS reveals that the δ to α transition corresponds to a change in the unit cell dimensions, evidenced by an increase in the d-spacing. This implies a more efficient chain packing in the crystal, for both samples, in the δ phase (lower d-spacing at low temperatures) than in the α phase (higher d-spacing at high temperatures). The chain packing differences are explained through in-situ FT-IR measurements that show the transition from ordered (δ phase) to disordered (α phase) methylene chain conformations.We would like to acknowledge financial support provided by the National Key R&D Program of China (2017YFE0117800) and the National Natural Science Foundation of China (51820105005, 21922308, and 52050410327). We also acknowledge financial support from the BIODEST project; this project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie Grant Agreement No. 778092. This work has also received funding from MINECO through project MAT2017-83014-C2-1-P and from the Basque Government through grant IT1309-19. R.A.P.-C is supported by the China Postdoctoral Science Foundation (2020M670462). G.L. is grateful to the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Y201908). We also thank the BSRF (beamline 1W2A) for providing beamtime

Synergistic theoretical and experimental study on the ion dynamics of bis(trifluoromethanesulfonyl)imide-based alkali metal salts for solid polymer electrolytes

Model validation of a well-known class of solid polymer electrolyte (SPE) is utilized to predict the ionic structure and ion dynamics of alternative alkali metal ions, leading to advancements in Na-, K-, and Cs-based SPEs for solid-state alkali metal batteries. A comprehensive study based on molecular dynamics (MD) is conducted to simulate ion coordination and the ion transport properties of poly(ethylene oxide) (PEO) with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt across various LiTFSI concentrations. Through validation of the MD simulation results with experimental techniques, we gain a deeper understanding of the ionic structure and dynamics in the PEO/LiTFSI system. This computational approach is then extended to predict ion coordination and transport properties of alternative alkali metal ions. The ionic structure in PEO/LiTFSI is significantly influenced by the LiTFSI concentration, resulting in different lithium-ion transport mechanisms for highly concentrated or diluted systems. Substituting lithium with sodium, potassium, and cesium reveals a weaker cation-PEO coordination for the larger cesium-ion. However, sodium-ion based SPEs exhibit the highest cation transport number, indicating the crucial interplay between salt dissociation and cation-PEO coordination for achieving optimal performance in alkali metal SPEs.The research was supported by funding as a part of the DESTINY PhD program, funded by the European Union's Horizon2020 research and innovation program under the Marie Skłodowska-Curie Actions COFUND (Grant No. 945357), and funding through the Basque Government PhD Grant. The authors also acknowledge funding from ‘Departamento de Educación, Política Lingüística y Cultura del Gobierno Vasco’ (Grant No. IT1358-22), the Basque Government (PRE_2022_1_0034), and thank SGI/IZO-SGIker UPV/EHU for providing supercomputing resources

Molecular-Level Insight into Charge Carrier Transport and Speciation in Solid Polymer Electrolytes by Chemically Tuning Both Polymer and Lithium Salt

The advent of Li-metal batteries has seen progress toward studies focused on the chemical modification of solid polymer electrolytes, involving tuning either polymer or Li salt properties to enhance the overall cell performance. This study encompasses chemically modifying simultaneously both polymer matrix and lithium salt by assessing ion coordination environments, ion transport mechanisms, and molecular speciation. First, commercially used lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt is taken as a reference, where F atoms become partially substituted by one or two H atoms in the −CF3 moieties of LiTFSI. These substitutions lead to the formation of lithium(difluoromethanesulfonyl)(trifluoromethanesulfonyl)imide (LiDFTFSI) and lithium bis(difluoromethanesulfonyl)imide (LiDFSI) salts. Both lithium salts promote anion immobilization and increase the lithium transference number. Second, we show that exchanging archetypal poly(ethylene oxide) (PEO) with poly(ε-caprolactone) (PCL) significantly changes charge carrier speciation. Studying the ionic structures of these polymer/Li salt combinations (LiTFSI, LiDFTFSI or LiDFSI with PEO or PCL) by combining molecular dynamics simulations and a range of experimental techniques, we provide atomistic insights to understand the solvation structure and synergistic effects that impact macroscopic properties, such as Li+ conductivity and transference number.The authors acknowledge support from the European Commission grant for Erasmus Mundus Joint Master’s Degree MESC+ under Framework Agreement Number 2018-1424/001-001-EMJMD, the EU Marie Sklodowska-Curie COFUND DESTINY project under Grant Agreement No. 945357, and the Basque Government PhD Grant. H.M. acknowledges funding from the “Departamento de Educación, Política Lingüística y Cultura del Gobierno Vasco” (Grant IT1358-22). They also thank SGI/IZO-SGIker UPV/EHU for supercomputing resources

Polycarbonates innovants utilisés comme polyélectrolytes solides dans les batteries lithium

The 21st century must address new challenges. The highly qualified life, demanded by modern society, requires constant developments. Energy is the essential ingredient for the economic and social development. The technological revolution that we are now suffering has as a principle the energy produced by coal, oil, and gas. However, the consumption of these energy sources are limited and additionally, during the last decades have been strongly criticized due to the high CO2 emissions released. Besides, the energy produced by renewable energies are promising alternative supplies to limited non-renewable resources. Little by little, the use of fuel-based energy sources will be reduced and renewable solar energy, wind power, hydropower, geothermal energy and bioenergy will be settled in our life. Nevertheless, due to the intermittent availability of these type of resources, good energy storage systems have to be designed. Among the all systems, electrochemical energy storage systems (EESS)s seem to be the best alternative for the use of portable electronics, electric vehicles and smart grid facilities.Generally, a battery contains a liquid electrolyte on it, which is based on a salt dissolved in a liquid organic solvent. This solvent is known to be toxic and highly flammable. Great efforts have been devoted to design safe electrolytes. Thus, polymer electrolytes have been proposed as safe materials. Nevertheless, the ionic conductivity, lithium transference number and electrochemical stability window should be addressed in order to be used in different applications. In this direction, in this thesis different polycarbonates have been proposed as promising host materials and they have been evaluated in as safe electrolytes.E 21ème siècle doit faire face à de nouveaux défis sociétaux et environnementaux. Pour cela, la gestion de l’énergie est un élément clé et en particulier le développement des énergies renouvelables. Progressivement les énergies basées sur le solaire, l’éolienne, l’hydraulique, la géothermie et les bio-ressources prennent le pas sur les énergies fossiles. Néanmoins, ces sources d’énergie sont bien souvent intermittentes, par conséquent, il est indispensable de développer des systèmes de stockage d'énergie fiables. Parmi toutes les options le stockage électrochimique semble être le plus prometteur pour les appareils électroniques, les véhicules électriques ainsi que les réseaux. Aujourd’hui, même si les batteries lithium-ion sont largement répandues, car relativement performantes, il reste indispensable de concevoir et de développer de nouvelles batteries répondant mieux encore aux nouvelles contraintes.Une batterie classique est constituée de deux électrodes et entre les deux se trouve l’électrolyte. Actuellement, et en général, dans les batteries commercialisées l’électrolyte est un liquide constitué d’un sel de lithium dissout dans un solvant organique. Celui-ci présente plusieurs risques : i) d’inflammabilité ; ii) de fuite ; iii) de volatilité ; et iv) de toxicité. Ainsi, des recherches sont menées pour développer de nouveaux matériaux polymériques, qui en plus de répondre aux risques mentionnés précédemment, cherchent à optimiser les propriétés de : conductivité ionique, nombre de transport, stabilité électrochimique, stabilité thermique, stabilité mécanique, etc. Parmi les polymères envisagés, les polycarbonates ont montré ces dernières années des propriétés très intéressantes. Dans ce contexte, au cours de la thèse, plusieurs familles de polycarbonates ont été synthétisées par polycondensation, puis évaluées en tant qu'électrolytes polymères solides afin de mettre en évidence l'impact de la structure chimique sur les performances

Innovative polycarbonates for lithium conducting polymer electrolytes

205 p.The highly qualified life, demanded by the society of the 21st century, requires constant scientific and technological developments. Energy is the essential ingredient for the economic and social development. In order to provide, clean energy, safe energy storage system has to be developed. The continuous research on polymer electrolytes will lead us into a promising energy storage system. Up to now, poly(ethylene oxide) (PEO) has been extensively explored polymer matrix in solid polymer electrolytes for lithium batteries. However, recently, polycarbonate-solid polymer electrolytes show considerable enhancements respect to PEO-solid polymer electrolytes, such as improved lithium conductivity and electrochemical stability. The main objective of this thesis is to evaluate and compare new polycarbonates¿ structures as SPEs in lithium batteries. For this purpose, the versatile and simple polycondensation technique was chosen as synthetic tool to develop polycarbonates. This synthetic method allowed to easily change the functionality of the diol and the properties of the polycarbonates, and therefore, to analyze the consequences in polymer electrolytes.Université de Pau et des Pays de l'Adour Polymat JPREM: Institut des sciences analytiques et de physics-chimie pour l'environnement et les matériau