A star-shaped single lithium-ion conducting copolymer by grafting a POSS nanoparticle

Towards ambient temperature operation of Li metal batteries using UV-Crosslinked single-ion electrospun electrolytes

In spite of the fact that lithium metal batteries (LMBs) facilitate the diversification of energy storage technologies, their electrochemical reversibility and stability have long been constrained by side reactions and lithium dendrite problems. While single-ion conducting polymer electrolytes (SICPEs) possess unique advantages of suppressing Li dendrite growth, they deal with difficulties in practical applications due to their slow ion transport in general application scenarios at ∼25 °C. In this study, we develop novel bifunctional lithium salts with negative sulfonylimide (-SO₂N(^-)SO₂-) anions mounted between two styrene reactive groups, which is capable of constructing 3D cross-linked networks with multiscale reticulated ion nanochannels, resulting in the uniform and rapid distribution of Li⁺ ions in the crosslinked electrolyte. To verify the feasibility of our strategy, we designed PVDF-HFP-based SICPEs and the obtained electrolyte exhibits high thermal stability, outstanding Li⁺ transference number (0.95), pleasing ionic conductivity (0.722 mS cm^-1), and broad chemical window (greater than5.85 V) at ambient temperature. As a result of the electrolyte structural merits, the Li||LFP cells displayed excellent cycling stability (96.4% reversible capacities after 300 cycles at 0.2C) without additional auxiliary heating. This ingenious strategy is expected to providing a new perspective for advanced performance and high safety LMBs.

Recent Development in Topological Polymer Electrolytes for Rechargeable Lithium Batteries

Solid polymer electrolytes (SPEs) are still being considered as a candidate to replace liquid electrolytes for high-safety and flexible lithium batteries due to their superiorities including light-weight, good flexibility, and shape versatility. However, inefficient ion transportation of linear polymer electrolytes is still the biggest challenge. To improve ion transport capacity, developing novel polymer electrolytes are supposed to be an effective strategy. Nonlinear topological structures such as hyperbranched, star-shaped, comb-like, and brush-like types have highly branched features. Compared with linear polymer electrolytes, topological polymer electrolytes possess more functional groups, lower crystallization, glass transition temperature, and better solubility. Especially, a large number of functional groups are beneficial to dissociation of lithium salt for improving the ion conductivity. Furthermore, topological polymers have strong design ability to meet the requirements of comprehensive performances of SPEs. In this review, the recent development in topological polymer electrolytes is summarized and their design thought is analyzed. Outlooks are also provided for the development of future SPEs. It is expected that this review can raise a strong interest in the structural design of advanced polymer electrolyte, which can give inspirations for future research on novel SPEs and promote the development of next-generation high-safety flexible energy storage devices.

Synthesis and Molecular Characterization of Well-defined Polyanion Miktoarm Star Copolymers

Over the last year, the synthesis of polyanion copolymers has attracted considerable attention for their utilization in single-ion electrolytes in lithium battery applications. Morphology has a significant impact on the...

Investigating miscibility and lithium ion transport in blends of poly(ethylene oxide) with a polyanion containing precisely-spaced delocalized charges

Synthesis of a precision single ion conductor with a phenylsulfonyl (TFSI) lithium salt pendant at every 5th carbon is reported and miscibility, conductivity, and transference studies are performed upon blending with PEO at varying compositions.

Progress in Solid Polymer Electrolytes for Lithium-Ion Batteries and Beyond

Solid-state polymer electrolytes (SPEs) for high electrochemical performance lithium-ion batteries have received considerable attention due to their unique characteristics; they are not prone to leakage, and they exhibit low flammability, excellent processability, good flexibility, high safety levels, and superior thermal stability. However, current SPEs are far from commercialization, mainly due to the low ionic conductivity, low Li⁺ transference number (t_Li+ ), poor electrode/electrolyte interface contact, narrow electrochemical oxidation window, and poor long-term stability of Li metal. Recent work on improving electrochemical performance and these aspects of SPEs are summarized systematically here with a particular focus on the underlying mechanisms, and the improvement strategies are also proposed. This review could lead to a deeper consideration of the issues and solutions affecting the application of SPEs and pave a new pathway to safe, high-performance lithium-ion batteries.

Polymer-Ligated Nanocrystals Enabled by Nonlinear Block Copolymer Nanoreactors: Synthesis, Properties, and Applications

The past several decades have witnessed substantial advances in synthesis and self-assembly of inorganic nanocrystals (NCs) due largely to their size- and shape-dependent properties for use in optics, optoelectronics, catalysis, energy conversion and storage, nanotechnology, and biomedical applications. Among various routes to NCs, the nonlinear block copolymer (BCP) nanoreactor technique has recently emerged as a general yet robust strategy for crafting a rich diversity of NCs of interest with precisely controlled dimensions, compositions, architectures, and surface chemistry. It is notable that nonlinear BCPs are unimolecular micelles, where each block copolymer arm of nonlinear BCP is covalently connected to a central core or polymer backbone. As such, their structures are static and stable, representing a class of functional polymers with complex architecture for directing the synthesis of NCs. In this review, recent progress in synthesizing NCs by capitalizing on two sets of nonlinear BCPs as nanoreactors are discussed. They are star-shaped BCPs for producing 0D spherical nanoparticles, including plain, hollow, and core-shell nanoparticles, and bottlebrush-like BCPs for creating 1D plain and core/shell nanorods (and nanowires) as well as nanotubes. As the surface of these NCs is intimately tethered with the outer blocks of nonlinear BCPs used, they can thus be regarded as polymer-ligated NCs (i.e., hairy NCs). First, the rational design and synthesis of nonlinear BCPs via controlled/living radical polymerizations is introduced. Subsequently, their use as the NC-directing nanoreactors to yield monodisperse nanoparticles and nanorods with judiciously engineered dimensions, compositions, and surface chemistry is examined. Afterward, the intriguing properties of such polymer-ligated NCs, which are found to depend sensitively on their sizes, architectures, and functionalities of surface polymer hairs, are highlighted. Some practical applications of these polymer-ligated NCs for energy conversion and storage and drug delivery are then discussed. Finally, challenges and opportunities in this rapidly evolving field are presented.

Non-solvating, side-chain polymer electrolytes as lithium single-ion conductors: synthesis and ion transport characterization

Non-solvating, side-chain polymer electrolytes with more dissociable pendent anion chemistries exhibit a dielectric relaxation dominated lithium ion transport mechanism.

Study on Surface Properties of Aramid Fiber Modified in Supercritical Carbon Dioxide by Glycidyl-POSS

The outstanding diffusivity and permeability of supercritical carbon dioxide (scCO₂) are extremely beneficial for grafting reaction. In this work, aramid fibers (AF) are modified in scCO₂ by glycidyl-polyhedral oliomeric silsesquioxane (POSS) with 2-ethyl-4-methylimidazole (2E4MZ) on the basis of cleaning with acetone. The surface morphology and chemical structure of the modified AF were measured and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Scanning electron microscope (SEM), Thermogravimetric (TG), and Atomic force microscope (AFM). The interfacial shear strength (IFSS) was measured by a micro-bond pull-out test, then the modified AF/EP composites were prepared and the interlaminar shear strength (ILSS) was characterized. Research has shown that some of the glycidyl-POSS molecular chains permeated into the surface of the fiber and grafted onto the surface of the AF after modification, and the other glycidyl-POSS self-assembled on the surface of the fiber. XPS indicated the introduction of C–O and –COO–, which confirmed the existence of chemical reactions between AF and glycidyl-POSS. AFM and SEM images revealed that 2E4MZ, not only promoted the grafting reaction of glycidyl-POSS, but also intensified the self-assembly of glycidyl-POSS, both of which increased the roughness of the fiber. A monofilament tensile test and micro-bond pull-out test showed that there was a negative effect on the tensile strength after scCO₂ processing. The tensile strength of modified AF, with glycidyl-POSS, increased the highest strength of 25.7 cN dtex⁻¹, which was 8% higher than that of pristine AF. The improvement of ILS roughness and the polar chemical groups produced in grafting reaction. These results indicated that AF, treated in scCO₂, with glycidyl-POSS, which is a suitable way of fiber modification, can significantly improve the surface adhesion of AF reinforced composites.

Toughening of POSS-MPS composites with low dielectric constant prepared with structure controllable micro/mesoporous nanoparticles

In this work, we developed a modified calcination and extraction method to obtain controllable micro/mesoporous nanoparticle samples POSS–MPS, which were synthesized through glycidyl polyhedral oligomeric silsesquioxane (G-POSS) grafting with aminopropyl-functionalized mesoporous silica (AP-MPS). The POSS–MPS was introduced into the cyanate ester (CE) matrix to optimize the dielectric properties and enhance the toughness of the POSS–MPS/CE nanocomposite. The structure of the hybrid was characterized by FTIR and SEM. The dispersion properties, mechanical properties, dielectric properties and thermal performance were also studied. The results showed that both the C-POSS–MPS and E-POSS–MPS uniformly distribute in the CE matrix with the content of 0.5–4 wt%. The impact strength increased 52% and 60% separately with 2 wt% C-POSS–MPS and E-POSS–MPS addition respectively. The introduction of E-POSS–MPS particles can significantly decrease the dielectric loss value of the POSS–MPS/CE composites to 0.00498, which is of potential in wave transparent composites and structures.

A promising method to improve the performance of CE composites via combining advantages of POSS and MPS.

Synthesis of POSS-functionalized liquid crystalline block copolymers via RAFT polymerization for stabilizing blue phase helical soft superstructures

A study of the phase transition behaviors of blue phase liquid crystals containing different amounts of POSS-functionalized LC BCPs.

Synthesis of naturally-derived macromolecules through simplified electrochemically mediated ATRP

The flavonoid-based macroinitiator was received for the first time by the transesterification reaction of quercetin with 2-bromoisobutyryl bromide. In accordance with the "grafting from" strategy, a naturally-occurring star-like polymer with a polar 3,3',4',5,6-pentahydroxyflavone core and hydrophobic poly(tert-butyl acrylate) (PtBA) side arms was synthesized via a simplified electrochemically mediated ATRP (seATRP), utilizing only 78 ppm by weight (wt) of a catalytic CuII complex. To demonstrate the possibility of temporal control, seATRP was carried out utilizing a multiple-step potential electrolysis. The rate of the polymerizations was well-controlled by applying optimal potential values during preparative electrolysis to prevent the possibility of intermolecular coupling of the growing polymer arms. This appears to be the first report using on-demand seATRP for the synthesis of QC-(PtBA-Br)5pseudo-star polymers. The naturally-derived macromolecules showed narrow MWDs (Đ = 1.08-1.11). 1H NMR spectral results confirm the formation of quercetin-based polymers. These new flavonoid-based polymer materials may find applications as antifouling coatings and drug delivery systems.

Block Copolymers: Synthesis, Self-Assembly, and Applications

Research on block copolymers (BCPs) has played a critical role in the development of polymer chemistry, with numerous pivotal contributions that have advanced our ability to prepare, characterize, theoretically model, and technologically exploit this class of materials in a myriad of ways in the fields of chemistry, physics, material sciences, and biological and medical sciences. The breathtaking progress has been driven by the advancement in experimental techniques enabling the synthesis and characterization of a wide range of block copolymers with tailored composition, architectures, and properties. In this review, we briefly discussed the recent progress in BCP synthesis, followed by a discussion of the fundamentals of self-assembly of BCPs along with their applications.