Research Field 4

Li, C. et. al., Macromol. Raid Commun., 2023,  2300464,  https://doi.org/10.1002/marc.202300464 

Hydrogen bonds (H-bonds) are highly sensitive to the surrounding environments owing to their dipolar nature, with polar solvents kown to significantly weaken H-bonds. Herein, the stability of the H-bonding motif ureidopyrimidinone (UPy) is investigated, embedded into a highly polar polymeric ionic liquid (PIL) consisting of pendant pyrrolidinium bis(trifluoromethylsulfonyl)imide (IL) moieties, to study the influence of such ionic environments on the UPy H-bonds. The content of the surrounding IL is changed by addition of an additional low molecular weight IL to further boost the IL content around the UPy moieties in molar ratios of UPy/IL ranging from 1/4 up to 1/113, thereby promoting the polar microenvironment around the UPy-H-bonds. Variable-temperature solid-state MAS NMR spectroscopy and FT-IR spectroscopy demonstrate that the UPy H-bonds are largely present as (UPy-) dimers, but sensitive to elevated temperatures (>70 °C). Subsequent rheology and DSC studies reveal that the ILs only solvate the polymeric chains but do not interfere with the UPy-dimer H-bonds, thus accounting for their high stability and applicability in many material systems. © 2023 The Authors. Macromolecular Rapid Communications published by Wiley‐VCH GmbH

Katcharava, Z. et al., RSC Advances, 2023, 14435-14442,

https://doi.org/10.1039/D3RA02396F

Polymer electrolytes (PEs) are a promising alternative to overcome shortcomings of conventional lithium ion batteries (LiBs) and make them safer for users. Introduction of self-healing features in PEs additionally leads to prolonged life-time of LIBs, thus tackling cost and environmental issues. We here present solvent free, self-healable, reprocessable, thermally stable, conductive poly(ionic liquid) (PIL) consisting of pyrrolidinium-based repeating units. The dynamic boronic ester linkages allow reprocessing (at 40 °C), reshaping and self-healing ability of PEs. Such vitrimeric PILs rcan be subjected to 3D printing via FDM, offering the possibility to design batteries with more complex and diverse architectures. Published with a permission of the Royal Society of Chemistry 2023.

Li, C. et al., Polymers, 2022, 4090,

https://doi.org/10.3390/polym14194090

Within the era of battery technology, the urgent demand for improved and safer electrolytes is immanent. In this work, novel electrolytes, based on pyrrolidinium-bistrifluoromethanesulfonyl-imide polymeric ionic liquids (POILs), equipped with quadrupolar hydrogen-bonding moieties of ureido-pyrimidinone (UPy) to mediate self-healing properties were generated. By combining the results from differential scanning calorimetry (DSC), broadband dielectric spectroscopy (BDS), and rheology, a decoupled conductivity of the POILs from the glass transition was revealed. Tensile tests for both pristine and self-healed samples, evidenced a rational design of self-healing electrolytes bearing both hydrogen bonding moieties and low-molecular-weight polymeric ionic liquids.

Zhou, X. et al., ACS Applied Engineering Materials, 2023, accepted,

https://doi.org/10.1021/acsaenm.3c00286

Vitrimers have been widely employed in self-healing, recyclable, and shape-shifting materials. However, the application of catalyst-free vitrimers to create self-healable and mechanically robust gel polymer electrolytes (GPEs) remains a challenge, often limiting the potential of vitrimer-based materials. Herein, we utilized a catalyst-free dynamic covalent bond (silyl ether) as a linkage to prepare self-healable and mechanically robust GPEs, which are fully reprocessable. By incorporating polymeric ionic liquids into the dynamically cross-linked networks, both ion conductivity and mechanical properties can be flexibly tuned. This dynamic feature enables self-healing and allows for reprocessing via embedding of such dynamic covalent networks into the GPEs, exhibiting good ion conductivites of 0.13 mS/cm at 20 °C and 1.88 mS/cm at 80 °C. Furthermore, the elastic modulus of the GPEs could reach a value of 0.24 MPa and was able to persist through electrode-volume expansions during charging/discharging, indicating promising applications for this type of dynamic bond in sustainable solid electrolytes. Copyright © 2023, American Chemical Society.

Katcharava, Z. et al., RSC Advances, 2023, 14435-14442,

https://doi.org/10.1039/D3RA02396F

Polymer electrolytes (PEs) are a promising alternative to overcome shortcomings of conventional lithium ion batteries (LiBs) and make them safer for users. Introduction of self-healing features in PEs additionally leads to prolonged life-time of LIBs, thus tackling cost and environmental issues. We here present solvent free, self-healable, reprocessable, thermally stable, conductive poly(ionic liquid) (PIL) consisting of pyrrolidinium-based repeating units. The dynamic boronic ester linkages allow reprocessing (at 40 °C), reshaping and self-healing ability of PEs. Such vitrimeric PILs rcan be subjected to 3D printing via FDM, offering the possibility to design batteries with more complex and diverse architectures. Published with a permission of the Royal Society of Chemistry 2023.

Marinow, A. et al., Polymers, 2023, 1145,

https://doi.org/10.3390/polym15051145

The integration of polymer materials with self-healing features into advanced lithium batteries is a promising and attractive approach to mitigate degradation and, thus, improve the performance and reliability of batteries. This paper comprehensively reviews various categories of self-healing polymer materials for application as electrolytes and adaptive coatings for electrodes in lithium-ion (LIBs) and lithium metal batteries (LMBs). We discuss the opportunities and current challenges in the development of self-healable polymeric materials for lithium batteries in terms of their synthesis, characterization and underlying self-healing mechanism, as well as performance, validation and optimization.

Chenming Li , et al. Polymers, 2022, 14, 4090, DOI:https://doi.org/10.3390/polym14194090

Within the era of battery technology, the urgent demand for improved and safer electrolytes is immanent. In this work, novel electrolytes, based on pyrrolidinium-bistrifluoromethanesulfonyl-imide polymeric ionic liquids (POILs), equipped with quadrupolar hydrogen-bonding moieties of ureido-pyrimidinone (UPy) to mediate self-healing properties are generated. The polymers display good conductivities as well as a self-healing efficiency of up to 88 %, in turn evidencing a rational design of self-healing electrolytes bearing, both hydrogen bonding moieties and low-molecular-weight polymeric ionic liquids.

Katacharava, Z., et al. Nanomaterials 2022, DOI:https://doi.org/10.3390/nano12111859

We here demonstrate the preparation of composite polymer electrolytes (CPEs) for Li-ion batteries, applicable for 3D printing process via fused deposition modeling. Based on composites of modified (H-bonding) poly(ethylene glycol) (PEG), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) and SiO2-based nanofillers we introduce self-healing into the electrolyte system. The composite electrolyte PEG 1500 UPy2/LiTFSI (EO:Li 5:1) mixed with 15% NP-IL was successfully 3D printed, revealing its suitability for application as printable composite electrolyte.

Rupp, H.. et. al. Frontiers in Chemistry, 2021, 9, 771974, https://doi.org/10.3389/fchem.2021.771974

Additive manufacturing has significantly changed polymer science and technology by engineering complex material-shapes and compositions. With the advent of dynamic properties in polymeric materials as a fundamental principle to achieve e.g. self-healing properties, the use of supramolecular chemistry as a tool for molecular ordering has become important. By adjusting molecular, nanoscopic (supramolecular) bonds in polymers, rheological properties, immanent for 3D printing can be adjusted, resulting in shape persistence and improved printing. We here review recent progress in 3D printing of supramolecular polymers, with a focus on fused deposition modelling (FMD) to overcome some of its limitations still being present up-to-date.