One-Component Nanocomposites Made from Diblock Copolymer Grafted Cellulose Nanocrystals.

Cellulose nanocrystals (CNCs) are bio-based, rod-like, high-aspect-ratio nanoparticles with high stiffness and strength and are widely used as a reinforcing nanofiller in polymer nanocomposites. However, due to hydrogen-bond formation between the large number of hydroxyl groups on their surface, CNCs are prone to aggregate, especially in nonpolar polymer matrices. One possibility to overcome this problem is to graft polymers from the CNCs' surfaces and to process the resulting "hairy nanoparticles" (HNPs) into one-component nanocomposites (OCNs) in which the polymer matrix and CNC filler are covalently connected. Here, we report OCNs based on HNPs that were synthesized by grafting gradient diblock copolymers onto CNCs via surface-initiated atom transfer radical polymerization. The inner block (toward the CNCs) is composed of poly(methyl acrylate) (PMA), and the outer block comprises a gradient copolymer rich in poly(methyl methacrylate) (PMMA). The OCNs based on such HNPs microphase separate into a rubbery poly(methyl acrylate) phase that dissipates mechanical energy and imparts toughness, a glassy PMMA phase that provides strength and stiffness, and well-dispersed CNCs that further reinforce the materials. This design afforded OCNs that display a considerably higher stiffness and strength than reference diblock copolymers without the CNCs. At the same time, the extensibility remains high and the toughness is increased up to 5-fold relative to the reference materials.

Carbon Dioxide Capture: Current Status and Future Prospects.

The surge in greenhouse gas emissions, predominantly in the form of carbon dioxide (CO2) spurred by the Industrial Revolution, has surpassed the critical threshold of 400 ppm, fueling global warming, ocean acidification, and climate change. To mitigate the adverse effects of these emissions and limit the global temperature rise to below 2 °C, the ambitious target of achieving net zero emissions by 2050 was established in the Paris Agreement. Current state-of-the-art technologies, such as amine scrubbing, remain problematic owing to their high energy requirements, susceptibility to corrosion, and other operational challenges. Owing to the lack of suitable technologies coupled with escalating energy demand, there is still a significant amount of carbon dioxide being released into the atmosphere. Accordingly, there is an urgent need for the development of alternative technologies that offer high efficiency, low energy consumption, cost-effective installation, and operation. In this review, we delve into the emerging technologies poised to address these challenges, evaluating their maturity levels in comparison to existing commercially available solutions. Furthermore, we provide a brief overview of ongoing efforts aimed at commercializing these innovative technologies.

Interfacial Stabilization by Prelithiated Trithiocyanuric Acid as an Organic Additive in Sulfide-Based All-Solid-State Lithium Metal Batteries.

Sulfide-based all-solid-state battery (ASSB) with a lithium metal anode (LMA) is a promising candidate to surpass conventional Li-ion batteries owing to their inherent safety against fire hazards and potential to achieve a higher energy density. However, the narrow electrochemical stability window and chemical reactivity of the sulfide solid electrolyte towards the LMA results in interfacial degradation and poor electrochemical performance. In this direction, we introduce an organic additive approach, that is the mixing of prelithiated trithiocyanuric acid, Li3TCA, with Li6PS5Cl, to establish a stable interface while preserving high ionic conductivity. Including 2.5 wt % Li3TCA alleviates the decomposition of the electrolyte on the lithium metal interface, decreasing the Li2S content in the solid-electrolyte interface (SEI) thus forming a more stable interface. In Li|Li symmetric cells, this strategy enables a rise in the critical current density from 1.0 to 1.9 mA cm-2 and stable cycling for over 750 hours at a high current density of 1.0 mA cm-2. This approach also enables Li|NbO-NCM811 full cell to operate more than 500 cycles at 0.3 C.

Accelerated Reversible Conversion of Li2S2 to Li2S by Spidroin Regulated Li+ Flux for High-performance Li-Sulfur Batteries.

Regulating the transformation of sulfur species is the key to improving the electrochemical performance of lithium-sulfur (Li-S) batteries, in particular, to accelerate the reversible conversion between solid phase Li2S2 and Li2S. Herein, we introduced Spidroin, which is a main protein in spider silk, as a dual functional separator coating in Li-S batteries to effectively adsorb polysulfides via the sequence of amino acids in its primary structure and regulate Li+ flux through the ß-sheet of its secondary structure, thus accelerating the reversible transformation between Li2S2 and Li2S. Spidroin-based Li-S cells exhibited an exceptional electrochemical performance with a high specific capacity of  744.1 mAh g-1 at 5C and a high areal capacity of 7.5 mAh cm-2 at a low electrolyte-to-sulfur (E/S) ratio of 6 µL mgs-1 and a sulfur loading of 8.6 mgs cm-2.

Fully Conjugated Benzyne-Derived Three-Dimensional Porous Organic Polymers.

Porous organic polymers (POPs) have gained tremendous attention owing to their chemical tunability, stability and high surface areas. Whereas there are several examples of fully conjugated two-dimensional (2D) POPs, three-dimensional (3D) ones are rather challenging to realize in the absence of structural templates. Herein, we report the base-catalyzed direct synthesis of a fully conjugated 3D POPs, named benzyne-derived polymers (BDPs), containing biphenylene and tetraphenylene moieties starting from a simple bisbenzyne precursor, which undergoes [2+2] and [2+2+2+2] cycloaddition reactions to form BDPs primarily composed of biphenylene and tetraphenylene moieties. The resulting polymers exhibited ultramicroporous structures with surface areas up to 544 m2 g-1 and very high CO2 /N2 selectivities.

Porous organic polymers for CO2 capture, separation and conversion.

Porous organic polymers (POPs) have long been considered as prime candidates for carbon dioxide (CO2) capture, separation, and conversion. Especially their permanent porosity, structural tunability, stability and relatively low cost are key factors in such considerations. Whereas heteratom-rich microporous networks as well as their amine impregnation/functionalization have been actively exploited to boost the CO2 affinity of POPs, recently, the focus has shifted to engineering the pore environment, resulting in a new generation of highly microporous POPs rich in heteroatoms and featuring abundant catalytic sites for the capture and conversion of CO2 into value-added products. In this review, we aim to provide key insights into structure-property relationships governing the separation, capture and conversion of CO2 using POPs and highlight recent advances in the field.

Porous Organic Polymers for Selective Palladium Recovery and Heterogeneous Catalysis.

Palladium (Pd) recycling from waste materials is an important approach in order to meet the growing demand for Pd originating from its broad range of applications including automotive industry, electronics and catalysis. In this article, we discuss the design principles of solid-sorbents for efficient recovery of Pd from waste sources with a particular emphasis on porous organic polymers (POPs), which emerged as promising porous materials for Pd recovery due to their tunable chemical functionality, stability and porosity. We discuss the critical role of binding sites and porosity in the Pd uptake capacity, adsorption kinetics and selectivity. We also highlight the use of captured Pd within the polymer networks as heterogeneous catalysts for cross-coupling reactions.

Mixed-metal Ionothermal Synthesis of Metallophthalocyanine Covalent Organic Frameworks for CO2 Capture and Conversion.

Phthalocyanines (PCs) are intriguing building blocks owing to their stability, physicochemical and catalytic properties. Although PC-based polymers have been reported before, many suffer from relatively low stability, crystallinity, and low surface areas. Utilizing a mixed-metal salt ionothermal approach, we report the synthesis of a series of metallophthalocyanine-based covalent organic frameworks (COFs) starting from 1,2,4,5-tetracyanobenzene and 2,3,6,7-tetracyanoanthracene to form the corresponding COFs named M-pPPCs and M-anPPCs, respectively. The obtained COFs followed the Irving-Williams series in their metal contents, surface areas, and pore volume and featured excellent CO2 uptake capacities up to 7.6 mmol g-1 at 273 K, 1.1 bar. We also investigated the growth of the Co-pPPC and Co-anPPC on a highly conductive carbon nanofiber and demonstrated their high catalytic activity in the electrochemical CO2 reduction, which showed Faradaic efficiencies towards CO up to 74 % at -0.64 V vs. RHE.

Integrated Ring-Chain Design of a New Fluorinated Ether Solvent for High-Voltage Lithium-Metal Batteries.

Ether-based electrolytes offer promising features such as high lithium-ion solvation power and stable interface, yet their limited oxidation stability impedes application in high-voltage Li-metal batteries (LMBs). Whereas the fluorination of the ether backbone improves the oxidative stability, the resulting solvents lose their Li+ -solvation ability. Therefore, the rational molecular design of solvents is essential to combine high redox stability with good ionic conductivity. Here, we report the synthesis of a new high-voltage fluorinated ether solvent through integrated ring-chain molecular design, which can be used as a single solvent while retaining high-voltage stability. The controlled Li+ -solvation environment even at low-salt-concentration (1 M or 2 M) enables a uniform and compact Li anode and an outstanding cycling stability in the Li|NCM811 full cell (20 µm Li foil, N/P ratio of 4). These results show the impact of molecular design of electrolytes towards the utilization of LMBs.

Fully Conjugated Tetraoxa[8]circulene-Based Porous Semiconducting Polymers.

Tetraoxa[8]circulenes (TOCs) are a class of hetero[8]circulenes featuring a planar cyclooctatetraene core with a mixed aromatic/antiaromatic motif that governs their electronic properties. Polymeric TOCs (pTOCs) have been the subject of several computational simulations because they are predicted to be low-band-gap semiconductors, but they have not been available synthetically yet. Here, we report the first example of pTOCs, a new family of porous semiconductors, synthesized under ionothermal conditions through the intermolecular cyclization of 1,4,5,8-anthracene tetrone. pTOCs are porous, with surface areas up to 1656 m2 g-1 , and exhibit light-switchable and tunable semiconducting properties.

The Prospect of Dimensionality in Porous Semiconductors.

With the advent of silicon-based semiconductors, a plethora of previously unknown technologies became possible. The development of lightweight low-dimensional organic semiconductors followed soon after. However, the efficient charge/electron transfers enabled by the non-porous 3D structure of silicon is rather challenging to be realized by their (metal-)organic counterparts. Nevertheless, the demand for lighter, more efficient semiconductors is steadily increasing resulting in a growing interest in (metal-)organic semiconductors. These novel materials are faced with a variety of challenges originating from their chemical design, their packing and crystallinity. Although the effect of molecular design is quite well understood, the influence of dimensionality and the associated change in properties (porosity, packing, conjugation) is still an uncharted area in (metal-)organic semiconductors, yet highly important for their practical utilization. In this Minireview, an overview on the design and synthesis of porous semiconductors, with a particular emphasis on organic semiconductors, is presented and the influence of dimensionality is discussed.

Ionic Liquid Functionalized Gel Polymer Electrolytes for Stable Lithium Metal Batteries.

Metallic lithium (Li) is regarded as the ideal anode material in lithium-ion batteries due to its low electrochemical potential, highest theoretical energy density and low density. There are, however, still significant challenges to be addressed such as Li-dendrite growth and low interfacial stability, which impede the practical application of Li metal anodes. In order to circumvent these shortcomings, herein, we present a gel polymer electrolyte containing imidazolium ionic liquid end groups with a perfluorinated alkyl chain (F-IL) to achieve both high ionic conductivity and Li ion transference number by fundamentally altering the solubility of salt within the gel electrolyte through Lewis-acidic segments in the polymer backbone. Moreover, the presence of F-IL moieties decreased the binding affinity of Li cation towards the glycol chains, enabling a rapid transfer of Li cation within the gel network. These structural features enabled the immobilization of anions on the ionic liquid segments to alleviate the space-charge effect while promoting stronger anion coordination and weaker cation coordination in the Lewis-acidic polymers. Accordingly, we realized a high Li ion conductivity (9.16×10-3  S cm-1 ) and high Li ion transference number of 0.69 simultaneously, along with a good electrochemical stability up to 4.55 V, while effectively suppressing Li dendrite growth. Moreover, the gel polymer electrolyte exhibited stable cycling performance of the Li|Li symmetric cell of 9 mAh cm-2 for more than 1800 hours and retained 86.7 % of the original capacity after 250 cycles for lithium-sulfur (Li-S) full cell.

Tailor-made Functional Polymers for Energy Storage and Environmental Applications.

CO2 emissions into the atmosphere account for the majority of environmental challenges and its global impact in the form of climate change is well-documented. Accordingly, the development of new materials approaches to capture and convert CO2 into value-added products is essential. Whereas the increased availability of renewable energy is curbing our reliance on fossil fuels and decreasing CO2 emissions, the widespread adaptation of renewable energy still requires the development of high energy density batteries i.e., lithium ion batteries (LIBs). To address these energy and environmental challenges, our group has been developing porous organic polymers (POPs) with precise control over their porosity and surface chemistry for CO2 capture, separation and conversion. To realize simultaneous CO2 separation and conversion, we are also developing catalytically active two-dimensional membranes and POPs. In the area of LIBs, we have recognized the potential of supramolecular chemistry as a general strategy for solving the capacity-fading problem associated with high energy density electrode materials such as Li-metal, silicon and sulfur, which offer extremely high battery capacity compared to conventional LIBs. Accordingly, we have demonstrated how molecular-level design of one- and two-dimensional supramolecular polymers can be directly translated into an improved electrochemical performance in high energy density LIBs.

A Three-Dimensional Porous Organic Semiconductor Based on Fully sp2 -Hybridized Graphitic Polymer.

Dimensionality plays an important role in the charge transport properties of organic semiconductors. Although three-dimensional semiconductors, such as Si, are common in inorganic materials, imparting electrical conductivity to covalent three-dimensional organic polymers is challenging. Now, the synthesis of a three-dimensional π-conjugated porous organic polymer (3D p-POP) using catalyst-free Diels-Alder cycloaddition polymerization followed by acid-promoted aromatization is presented. With a surface area of 801 m2 g-1 , full conjugation throughout the carbon backbone, and an electrical conductivity of 6(2)×10-4  S cm-1 upon treatment with I2 vapor, the 3D p-POP is the first member of a new class of permanently porous 3D organic semiconductors.

Advances in Porous Organic Polymers for Efficient Water Capture.

Desiccant driven dehumidification for maintaining the proper humidity levels and atmospheric water capture with minimum energy penalty are important aspects in heat pumps, refrigeration, gas and liquid purifications, gas sensing, and clean water production for improved human health and comfort. Water adsorption by using nanoporous materials has emerged as a viable alternative to energy-intensive industrial processes, thus understanding the significance of their porosity, high surface areas, vast pore volumes, chemical and structural features relative to the water adsorption is quite important. In this review article, important features of nanoporous materials are presented, including zeolites, porous carbons, as well as crystalline and amorphous porous organic polymers (POPs) to define the interactions between the water molecules and the polar/non-polar functional groups on the surface of these nanoporous materials. In particular, focus is placed on the recent developments in POPs in the context of water capture as a result of their remarkable stability towards water and wide range of available synthetic routes and building blocks for their synthesis. We also highlighted recent approaches to increase the water sorption capacity of POPs by modifying their structure, morphology, porosity, and chemical functionality while emphasizing their promising future in this emerging area.

The emerging era of supramolecular polymeric binders in silicon anodes.

Silicon (Si) anode is among the most promising candidates for the next-generation high-capacity electrodes in Li-ion batteries owing to its unparalleled theoretical capacity (4200 mA h g-1 for Li4.4Si) that is approximately 10 times higher than that of commercialized graphitic anodes (372 mA h g-1 for LiC6). The battery community has witnessed substantial advances in research on new polymeric binders for silicon anodes mainly due to the shortcomings of conventional binders such as polyvinylidene difluoride (PVDF) to address problems caused by the massive volume change of Si (300%) upon (de)lithiation. Unlike conventional battery electrodes, polymeric binders have been shown to play an active role in silicon anodes to alleviate various capacity decay pathways. While the initial focus in binder research was primarily to maintain the electrode morphology, it has been recently shown that polymeric binders can in fact help to stabilize cracked Si microparticles along with the solid-electrolyte-interphase (SEI) layer, thus substantially improving the electrochemical performance. In this review article, we aim to provide an in-depth analysis and molecular-level design principles of polymeric binders for silicon anodes in terms of their chemical structure, superstructure, and supramolecular interactions to achieve good electrochemical performance. We further highlight that supramolecular chemistry offers practical tools to address challenging problems associated with emerging electrode materials in rechargeable batteries.

Lithium-Salt Mediated Synthesis of a Covalent Triazine Framework for Highly Stable Lithium Metal Batteries.

A new strategy for the synthesis of a covalent triazine framework (CTF-1) was introduced based on the cyclotrimerization reaction of 1,4-dicyanobenzene using lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) under ionothermal conditions. LiTFSI not only served as a catalyst, but also facilitated the in situ generation and homogeneous distribution of LiF particles across the framework. The hierarchical structure resulting upon integration of CTF-LiF onto an airlaid-paper (AP) offered unique features for lithium metal anodes, such as lithiophilicity from CTF, interface stabilization from LiF, and sufficient lithium storage space from AP. Based on this synergistic effect, the AP-CTF-LiF anode exhibited stable cycling performance even at a current density of 10 mA cm-2 .

Energy Band-Gap Engineering of Conjugated Microporous Polymers via Acidity-Dependent in Situ Cyclization.

Conjugated microporous polymers (CMPs) offer a unique structure integrating π-conjugated backbone into a porous network for the simultaneous transport of charges and materials. However, tuning electronic properties of CMPs so far has been limited to an approach of varying the monomers, and the precious metal catalysts are inevitably needed for the C-C coupling reaction. Here, we present a powerful strategy to synthesize CMPs and precisely tune their optical band gap and surface area through metal-free in situ cyclization reaction controlled by the acid strength of acid catalysts. Notably, the optical band gap of CMPs showed a linear relationship with the p Ka of acid catalysts, which provides us with the ability to obtain the desired band gap between 2.07 and 3.35 eV, falling in the range of the visible solar spectrum. Moreover, CMPs exhibited excellent textural properties such as microporosity and high specific surface area.

Epoxy-Functionalized Porous Organic Polymers via the Diels-Alder Cycloaddition Reaction for Atmospheric Water Capture.

The synthesis of highly microporous, epoxy-functionalized porous organic polymers (ep-POPs) by a one-pot, catalyst-free Diels-Alder cycloaddition polymerization is reported. The high oxygen content of ep-POPs offer efficient hydrogen-bonding sites for water molecules, thus leading to high water-uptake capacities up to 39.2-42.4 wt % under a wide temperature range of 5-45 °C, which covers the span of climatic conditions and manufacturing applications in which such materials might be used. Importantly, ep-POPs demonstrated regeneration temperatures as low as 55 °C, as well as excellent water stability, recyclability, and high specific surface areas up to 852 m2 g-1 .