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Designing compatible electrode–electrolyte interfaces is critical to achieve high and consistent performance and life span in next-generation rechargeable lithium batteries. In the study of nanoscopic interfaces, ab initio molecular dynamics (AIMD) simulations allow for a highly accurate description of interface dynamics and reactions. However, due to the high computational cost, simulations are limited in the size and time domains and therefore merit the need for a new interpretational approach that can deduce the long-term reactivity from such short yet highly accurate simulations. In this study, this is established by means of bond length distribution analysis through which the reactivity of key solid polymer electrolyte (SPE) polymer functional groups in contact with key electrode materials (graphite, silicon, lithium) and the influence of the electric field and temperature was successfully determined. Bond length distributions were found to respond to environmental changes and relate to the long-term reactivity in which the strength of electrode surface interactions and the accessibility of functional groups were found to be critical factors. Furthermore, the balancing of the SPE polymer mobility and functional group–electrode surface attraction, respectively, kinetic and thermodynamic properties, further suggests a selective spatial orientation of functional groups when exposed to an electric field, which could have great implications for low-temperature and high-current-density environments. The obtained knowledge on how reactive key SPE polymer functional groups are and also how their reactivity changes in terms of the electric field orientation effect could provide new insights for designing new stable SPE polymers.

In the rising advent of organic Li-ion positive electrode materials with increased energy content, chemistries with high redox potential and intrinsic oxidation stability remain a challenge. Here, we report the solid-phase reversible electrochemistry of the oximate organic redox functionality. The disclosed oximate chemistries, including cyclic, acyclic, aliphatic, and tetra-functional stereotypes, uncover the complex interplay between the molecular structure and the electroactivity. Among the exotic features, the most appealing one is the reversible electrochemical polymerization accompanying the charge storage process in solid phase, through intermolecular azodioxy bond coupling. The best-performing oximate delivers a high reversible capacity of 350 mAh g −1 at an average potential of 3.0 versus Li + /Li 0 , attaining 1 kWh kg −1 specific energy content at the material level metric. This work ascertains a strong link between electrochemistry, organic chemistry, and battery science by emphasizing on how different phases, mechanisms, and performances can be accessed using a single chemical functionality.

Green resources for lithium-based batteries excite many researchers due to their eco-friendly nature. In this work, a sustainable bio-based solid-state electrolyte was developed based on carbonated soybean oil (CSBO), obtained by organocatalyzed coupling of CO2 to epoxidized soybean oil. CSBO coupled with lithium bis(trifluoromethanesulfonyl)imide salt on a bio-based cellulose separator resulted in free-standing membranes. Those membranes on electrochemical measurements exhibited ionic conductivity of around 10−3 S cm−1 at 100 °C and around 10−6 S cm−1 at room temperature with wide electrochemical stability window (up to 4.6 V vs. Li/Li+) and transference number up to 0.39 at RT. Further investigations on the galvanostatic charge-discharge of LiFePO4 cathodes with CSBO-based electrolyte membranes and lithium metal anodes delivered the gravimetric capacity of 112 and 157 mAh g−1 at RT and 60 °C, respectively, providing a promising direction to further develop bio-based solid electrolytes for sustainable solid-state lithium batteries.

We study the linear viscoelastic properties of polymeric networks formed by poly( n-butyl acrylate) telechelic stars end-capped with 2,2:6,2″-terpyridine (Star-PnBA-tpy4) and two types of metal-ligand cross-links with different lifetimes. The influence of interactions, mediated by temperature, nature of metal ions, and ion content, on the linear viscoelastic behavior of both single and double dynamics transient networks is systematically investigated by small amplitude oscillatory shear and creep rheometry. The experimental results reveal that the dynamics of networks with two different metal-ligand cross-links is much faster than expected, characterized by the average sticker lifetime rather than a discrete contribution of each metal-ligand complex. We model the dynamics with the help of our modified tube-based time marching algorithm by accounting for both association/dissociation dynamics of metal-ligand coordination and the entanglement dynamics. Two parameters are defined in the model, namely, the proportion of dangling ends and the average time during which a sticker is free. This allows us to quantify the transient dynamics of the network and, in particular, to determine how the sticker dynamics depend on temperature and ion content.

An interesting activation phenomenon: Activation with cycling of a 3.8 V (vs. Na+/Na) redox process in the iron-rich Na0.6Fe1.2PO4 material unlocks new electrochemical mechanism for high-performance, low-cost and eco-friendly Na-ion cathodes

Coordination polymers (CPs) made of redox-active organic moieties and metal ions emerge as an important class of electroactive materials for battery applications. However, the design and synthesis of high voltage alkali-cation reservoir anionic CPs remains challenging, hindering their practical applications. Herein, we report a family of electrically conducting alkali-cation reservoir CPs with the general formula of A2-TM-PTtSA (wherein A = Li+, Na+, or K+; TM = Fe2+, Co2+, or Mn2+; and PTtSA = benzene-1,2,4,5-tetra-methylsulfonamide). The incorporation of transition metal centers not only enables intrinsic high electrical conductivity, but also shows an impressive redox potential increase of as high as 1 V as compared to A4-PTtSA analogues, resulting in a class of organometallic cathode materials with a high average redox potential of 2.95–3.25 V for Li-, Na- and K-ion batteries. A detailed structure – composition – physicochemical properties – performance correlation study is provided relying on experimental and computational analysis. The best performing candidate shows excellent rate capability (86% of the nominal capacity retained at 10C rate), remarkable cycling stability (96.5% after 1000 cycles), outstanding tolerance to low carbon content (5 wt%), high mass loading (50 mg cm−2), and extreme utilisation conditions of low earth orbit space environment tests. The significance of the disclosed alkali-ion reservoir cathodes is further emphasized by utilizing conventional Li-host graphite anode for full cell assembly, attaining a record voltage of 3 V in an organic cathode Li-ion proof-of-concept cell.

Solid-state polymer electrolytes are key components for future batteries with higher energy density as well as increased safety and processability. In this context, a solid polymer electrolyte is developed from statistical copolymers containing flame-retardant phosphonate units and ion-conductive cyclocarbonate moieties mixed with lithium salts. Ionic conductivity measured at room temperature for those copolymers (≈10−5 S cm−1) are in the same range as typical solid polymeric electrolytes not based on poly(ethylene oxide). Moreover, those copolymers electrolytes are stable in a wide electrochemical window (0.5 – 4.5 V vs Li+/Li) and at high temperature (>120 °C) and they lead to a better ionic conductivity than the corresponding homopolymer blends of a similar composition, which is explained by a better lithium salt solubility and better-defined ion-conduction pathways in case of the copolymer. Finally, it has demonstrated the possibility to have fire-retardant properties afforded by phosphonate groups in copolymers without impacting the ionic conductivity.

Herein, we describe the synthesis of the first boron nitride-doped polyphenylenic material obtained through a [4 + 2] cycloaddition reaction between a triethynyl borazine unit and a biscyclopentadienone derivative, which undergoes organogel formation in chlorinated solvents (the critical jellification concentration is 4% w/w in CHCl3). The polymer has been characterized extensively by Fourier-transform infrared spectroscopy, solid-state 13C NMR, solid-state 11B NMR, and by comparison with the isolated monomeric unit. Furthermore, the polymer gels formed in chlorinated solvents have been thoroughly characterized and studied, showing rheological properties comparable to those of polyacrylamide gels with a low crosslinker percentage. Given the thermal and chemical stability, the material was studied as a potential support for solid-state electrolytes. showing properties comparable to those of polyethylene glycol-based electrolytes, thus presenting great potential for the application of this new class of material in lithium-ion batteries.

The constant growth in the global energy demand together with the increasing awareness of clean and sustainable development has strongly pushed scientists to search for metal-free, low-cost, environmentally friendly functional energy-storage systems (ESSs). Among the reported organic electrode materials, carbonyl-based π-conjugated compounds show excellent rate capabilities and cycling stabilities and are powerful candidates for the next generation of rechargeable lithium-ion batteries (LIBs). Benefiting from the molecular structure versatility and design feasibility, the electrochemical properties of organic and polymeric materials can be easily tuned. This Review summarizes recent efforts in the search for carbonyl-based π-conjugated electrode materials in LIBs with a focus on the synthetic strategies developed to improve their electrochemical performance. The use of these materials in flexible, all-organic LIBs is highlighted as a unique direction towards widespread applications of LIBs.

Vinylidene fluoride (VDF)-based copolymers bearing pendant perfluoroalkyl ether groups for potential application in gel polymer electrolytes were synthesized via conventional radical copolymerization of VDF with a 2-trifluoromethacrylate monomer bearing pendant perfluoroalkyl ether groups [2,3,3,3-tetrafluoro-2-[1,1,2,3,3,3-hexafluoro-2-(perfluoropropoxy)propoxy]propyl 2-(trifluoromethyl)acrylate (MAF-PFE)]. Two kinds of initiators (hydrogenated and a perfluorinated highly branched persistent radical that released CF3• radical from 80 °C) were used. Molar masses ranged between 35 000 and ca. 50 000 g·mol–1. The synthesized poly(VDF-co-MAF-PFE) copolymers were evaluated in gel polymer electrolytes based on ionic liquids. With this aim, the poly(VDF-co-MAF-PFE) copolymers were mixed with lithium bis(trifluoromethanesulfonyl)imide and the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. Homogeneous gels with conductivity values at room temperature reaching up to 3 × 10–3 S·cm–1 were obtained, while the transference number of lithium ions was 0.12 at 40 °C. Finally, such electrolytes displayed an electrochemical stability window between 1.5 and 4.4 V as determined by cyclic voltamperometry measurements.

With higher energy density, flexibility, safe operation at both room temperature as well as high temperature, solid-state batteries technology has been strongly looked upon as superior diversion from conventional liquid electrolytes-based lithium batteries. Among various other class of polymers, there is strong need to focus on sustainable and yet better alternatives other than most researched polyethylene oxide (PEO). Poly(hydroxyurethanes) (PHU) owing to their high degree of structural tunability can be interesting candidates for Solid polymer electrolyte (SPE). Here, we synthesized bio-based PHU networks by facile ring-opening polymerization of carbonated soybean oil (CSBO) without catalyst. The existence of polyether and polyester provides the PHU network with soft segments while urethane linkage with hard segments. The lower Tg with higher thermal stability widespread its application at elevated temperature without melting and significant degradation. PHU shows remarkable adhesive properties to the surface of metal speculating better interfacial contact and stability. The electrochemical investigations exhibited decent ionic conductivity (> 10-4 at 60o C), electrochemical stability window (ESW > 4.5 V vs. Li/Li+) and transport properties allowing it to be explored for high voltage cathodes. Lithium ferrophosphate (LiFePO4) cells with PHU also demonstrated promising charge-discharge (> 100 mAhg-1 at 60o C) with the li-metal anode. The attempt to develop bio-based batteries materials are much required added step toward green and clean energy for a sustainable future.

Lithium-ion batteries are today among the most efficient devices for electrochemical energy storage. However, an improvement of their performance is required to address the challenges of modern grid management, portable technology, and electric mobility. One of the most important limitations to solve is the slow kinetics of redox reactions associated to inorganic cathodic materials, directly impacting on the charging time and the power characteristics of the cells. In sharp contrast, redox polymers such as poly(2,2,6,6-tetramethyl-1-piperidinyloxy methacrylate) (PTMA) exhibit fast redox reaction kinetics and pseudocapacitors characteristics. In this contribution, we have hybridized high energy Li(NixMnyCoz)O2 mixed oxides (NMC) with PTMA. In this hybrid cathode configuration, the higher voltage NMC (ca. 3.7 V vs. Li/Li+) is able to transfer its energy to the lower voltage PTMA (3.6 V vs. Li/Li+) improving the discharge power performances and allowing high power cathodes to be obtained. However, the NMC-PTMA hybrid cathodes show an important capacity fading. Our investigations indicate the presence of an interface degradation reaction between NMC and PTMA transforming NMC into an electrochemically dead material. Moreover, the aqueous process used here to prepare the cathode is also shown to enable the degradation of NMC. Indeed, once NMC is immersed in water, alkaline surface species dissolve, increasing the pH of the slurry, and corroding the aluminum current collector. Additionally, the NMC surface is altered due to delithiation which enables the interface degradation reaction to take place. This reaction by surface passivation of NMC particles did not succeed in preventing the interfacial degradation. Degradation was, however, notably decreased when Li(Ni0.8Mn0.1Co0.1)O2 NMC was used and even further when alumina-coated Li(Ni0.8Mn0.1Co0.1)O2 NMC was considered. For the latter at a 20C discharge rate, the hybrids presented higher power performances compared to the single constituents, clearly emphasizing the benefits of the hybrid cathode concept.

Lithium-ion batteries are today among the most efficient devices for electrochemical energy storage. However, an improvement of their performance is required to address the challenges of modern grid management, portable technology, and electric mobility. One of the most important limitations to solve is the slow kinetics of redox reactions associated to inorganic cathodic materials, directly impacting on the charging time and the power characteristics of the cells. In sharp contrast, redox polymers such as poly(2,2,6,6-tetramethyl-1-piperidinyloxy methacrylate) (PTMA) exhibit fast redox reaction kinetics and pseudocapacitors characteristics. In this contribution, we have hybridized high energy Li(NixMnyCoz)O2 mixed oxides (NMC) with PTMA. In this hybrid cathode configuration, the higher voltage NMC (ca. 3.7 V vs. Li/Li+) is able to transfer its energy to the lower voltage PTMA (3.6 V vs. Li/Li+) improving the discharge power performances and allowing high power cathodes to be obtained. However, the NMC-PTMA hybrid cathodes show an important capacity fading. Our investigations indicate the presence of an interface degradation reaction between NMC and PTMA transforming NMC into an electrochemically dead material. Moreover, the aqueous process used here to prepare the cathode is also shown to enable the degradation of NMC. Indeed, once NMC is immersed in water, alkaline surface species dissolve, increasing the pH of the slurry, and corroding the aluminum current collector. Additionally, the NMC surface is altered due to delithiation which enables the interface degradation reaction to take place. This reaction by surface passivation of NMC particles did not succeed in preventing the interfacial degradation. Degradation was, however, notably decreased when Li(Ni0.8Mn0.1Co0.1)O2 NMC was used and even further when alumina-coated Li(Ni0.8Mn0.1Co0.1)O2 NMC was considered. For the latter at a 20C discharge rate, the hybrids presented higher power performances compared to the single constituents, clearly emphasizing the benefits of the hybrid cathode concept.

New solid polymer electrolytes are of particular interest for next-generation high-energy batteries since they can overcome the limited voltage window of conventional polyether-based electrolytes. Herein, a flame-retardant phosphorus-containing polymer, poly(dimethyl(methacryloyloxy)methyl phosphonate) (PMAPC1) is introduced as a promising polymer matrix. Free-standing membranes are easily obtained by mixing PMAPC1 with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and a small amount of acetonitrile (AN). LiTFSI/AN mixed aggregates are formed that act as plasticizers and enable ionic conductivities up to 1.6 × 10-3 S cm-1 at 100 °C. The high content of LiTFSI used in our electrolytes leads to the formation of a stable LiF solid-electrolyte interphase, which can effectively suppress Li dendrites and the chemical degradation of AN in contact with Li. Accordingly the electrolyte membranes exhibit a wide electrochemical stability window above 4.7 V versus Li+/Li and fire-retardant properties due to the presence of the phosphorus-containing polymer. Atomistic molecular modeling simulations have been performed to determine the structure of the electrolytes on the microscopic scale and to rationalize the trends in ionic conductivity and the transport regime as a function of the electrolyte composition. Finally, our electrolyte membranes enable stable cycling performance for LiFePO4|PMAPC1 + LiTFSI + AN|Li batteries.

Hydrogels have reached momentum due to their potential application in a variety of fields including their ability to deliver active molecules upon application of a specific chemical or physical stimulus and to act as easily recyclable catalysts in a green chemistry approach. In this paper, we demonstrate that the same redox-responsive hydrogels based on polymer networks containing 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) stable nitroxide radicals and oligoethylene glycol methyl ether methacrylate (OEGMA) can be successfully used either for the electrochemically triggered release of aspirin or as catalysts for the oxidation of primary alcohols into aldehydes. For the first application, we take the opportunity of the positive charges present on the oxoammonium groups of oxidized TEMPO to encapsulate negatively charged aspirin molecules. The further electrochemical reduction of oxoammonium groups into nitroxide radicals triggers the release of aspirin molecules. For the second application, our hydrogels are swelled with benzylic alcohol and tert-butyl nitrite as co-catalyst and the temperature is raised to 50 °C to start the oxidation reaction. Interestingly enough, benzaldehyde is not miscible with our hydrogels and phase-separate on top of them allowing the easy recovery of the reaction product and the recyclability of the hydrogel catalyst.

The formation of micelles on surfaces by spin-coating dilute solutions of diblock, triblock, and tetrablock copoly(2-oxazoline)s in a non-selective solvent is demonstrated. The micelles are not preexistent in the initial solution but are formed during the evaporation of the solvent by precipitation of the least-soluble block. The morphology and size of the micelles vary according to the fraction of this block but are not dependent on the block order in the copolymer.

Well‐defined pyrene‐based poly(2,2,6,6‐tetramethylpiperidinyloxy‐4‐yl methacrylate) (PTMA) (co)polymers have been synthesized and combined with multi‐wall carbon nanotubes (CNTs) as electrode material for organic radical batteries. The influence of the number of pyrene pendent groups on the electrochemical response of the nanocomposite materials has been assessed, focusing on the capacity retention upon charge/discharge cycling and on the cycling rate. In parallel, the interactions between the polymethacrylate chains and the CNT surface have been investigated with molecular modeling techniques, to shed light on the nature and stability of the functionalized PTMA/CNT interface.

A tri-dimensional interweaving kinked silicon nanowires (k-SiNWs) assembly, with a Ni current collector co-integrated, is evaluated as electrode configuration for lithium ion batteries. The large-scale fabrication of k-SiNWs is based on a procedure for continuous metal assisted chemical etching of Si, supported by a chemical peeling step that enables the reuse of the Si substrate. The kinks are triggered by a simple, repetitive etch-quench sequence in a HF and H2O2-based etchant. We find that the inter-locking frameworks of k-SiNWs and multi-walled carbon nanotubes exhibit beneficial mechanical properties with a foam-like behavior amplified by the kinks and a suitable porosity for a minimal electrode deformation upon Li insertion. In addition, ionic liquid electrolyte systems associated with the integrated Ni current collector repress the detrimental effects related to the Si-Li alloying reaction, enabling high cycling stability with 80% capacity retention (1695 mAh/gSi) after 100 cycles. Areal capacities of 2.42 mAh/cm2 (1276 mAh/gelectrode) can be achieved at the maximum evaluated thickness (corresponding to 1.3 mgSi/cm2). This work emphasizes the versatility of the metal assisted chemical etching for the synthesis of advanced Si nanostructures for high performance lithium ion battery electrodes.

In this work, density functional theory is used to predict the voltage of newly designed PTMA-based radical molecules. Organic radical molecules have recently been tested as promising materials for secondary batteries due to their processability and structural diversity. In order to tune the redox potentials, we investigate the substitution of functional groups on the actual TEMPO organic radical. Our first-principles simulations predict voltages ranging between 3.4 and 6.2 V allowing for a fine-tuning of the corresponding voltage for specific needs.

The solid-state battery has drawn a huge interest with its motive to overcome the issues and challenges faced by batteries using conventional liquid electrolytes. The novel idea of using green approaches or bio-based sources for lithium batteries excites many researchers due to their eco-friendly, less carbon footprint in its synthesis and recycling at the end. In this work, we report a full bio-based solid-state electrolyte based on functionalised carbonated soybean oil (CSBO) obtained from the naturally occurring epoxidised soybean oil (ESBO) using CO2 and biomass. CSBO shows remarkable adhesive properties as characterized by rheological measurements owing to its bigger chains bearing multifunctional cyclic carbonates. LiTFSI salt reinforced CSBO was characterized following standard electrochemical measurements exhibiting ionic conductivity to ≈ 10–3 S cm–1 at 100 ºC and 10–5 S cm–1 at room temperature. The electrochemical window for this electrolyte was obtained to be 4.8 V (vs. Li/Li+) and transference number up to 0.31, allowing it to be explored for high voltage cathodes. CBSO shows stable stripping and plating behaviour for longer cycles making it a good candidate for higher columbic efficiency electrolyte batteries. We also demonstrated the galvanostatic charge-discharge of LiFePO4 (Lithium Ferrrophosphate, LFP) with CSBO electrolytes delivering the gravimetric capacity of 110 mAhg-1 and 150 mAhg-1 appx. at ambient room and higher temperature respectively. Therefore, our study provides a promising direction of developing bio-based solid electrolytes to facilitate progress in sustainability, cost-effective and safe manner to create a solid-state lithium-ion battery for global utilization. Figure 1

Electrochemical performances of LiMn2O4 (LMO) – poly (2,2,6,6-tetramethyl-1-piperinidyloxy-4-yl methacrylate) (PTMA) hybrid electrodes are investigated. Different constituent ratios are tested and the impact on the power and the cycling performances is discussed. Variable rate galvanostatic charge/discharge tests show improved energy-power performances and capacity retention of the hybrid LMO/PTMA electrodes when compared to pure LMO electrodes. This enhancement is correlated to a sequential power delivery mechanism by the fast kinetic component (PTMA) subsequently recharged by the high-energy constituent (LMO). Hybrid electrodes are shown to deliver higher energy and longer cycle life when subjected to power pulse tests. The combination of the PTMA power buffer component with the LMO high-energy sink proves the potential of the hybrid energy-power electrodes in pulsed discharge applications.

Water-soluble binders can enable greener and cost-effective Li-ion battery manufacturing by eliminating the standard fluorine-based formulations and associated organic solvents. The issue with water-based dispersions, however, remains the difficulty in stabilizing them, requiring additional processing complexity. Herein, we show that mechanochemical conversion of a regular poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) water-based dispersion produces a hydrogel that meets all the requirements as binder for lithium-ion battery electrode manufacture. We particularly highlight the suitable slurry rheology, improved adhesion, intrinsic electrical conductivity, large potential stability window and limited corrosion of metal current collectors and active electrode materials, compared to standard binder or regular PEDOT:PSS solution-based processing. When incorporating the active materials, conductive carbon and additives with PEDOT:PSS, the mechanochemical processing induces simultaneous binder gelation and fine mixing of the components. The formed slurries are stable, show no phase segregation when stored for months, and produce highly uniform thin (25 μm) to very thick (500 μm) films in a single coating step, with no material segregation even upon slow drying. In conjunction with PEDOT:PSS hydrogels, technologically relevant materials including silicon, tin, and graphite negative electrodes as well as LiCoO

Janus particles have built momentum in the last years owing to their unique structure and properties. In this review, we present an overview of the advances in the field of non-centrosymmetric Janus particles and discuss in detail the synthesis, self-assembly behavior, and physical properties as well as applications in various fields.

This work studies the linear viscoelastic properties of a series of low-dispersity poly(n-butyl acrylate) chains end-functionalized with 2,2′;6′,2″-terpyridine, able to self-associate by metal–ligand coordination. Depending on the architecture and functionality of the chains, the polymers self-assemble into different metallo-supramolecular bulk structures once metal ions are added. Linear building blocks (monofunctional or bifunctional) form longer chains while four-arm stars form networks. The properties of the obtained materials can be finely tuned depending on the length of the polymer chains and the type of metal. In this respect, enhanced control is gained over the dynamics of this class of metallo-supramolecular assemblies. Hence, they are extremely interesting for specific applications such as adhesives or mechanosensors.

Solid polymer electrolytes (SPEs) are prepared by mixing poly(2-oxo-1,3-dioxolan- 4-yl)methyl acrylate-random-n-butylacrylate) [P(cyCA-r-nBA)] statistical copolymers with bis(trifluoromethane)sulfonimide lithium salt. The P(cyCA-rnBA) copolymers are synthesized by reversible addition-fragmentation chain transfer polymerization and different molar masses as well as copolymer composition are targeted in order to study the influence of the molecular parameters on the thermal, mechanical, and electrochemical properties of the SPEs obtained after mixing the copolymers with lithium salts. In the investigated experimental window, it is shown that the thermal and mechanical properties of the SPEs mainly depend on the composition of the copolymer and are poorly influenced by the molar mass. In sharp contrast, the ionic conductivities are more deeply influenced by the molar mass than by the composition of the copolymers. In this respect ionic conductivity values ranging from 4.2 × 10−6 S cm−1 for the lower molar mass sample to 8 × 10−8 S cm−1 for the higher molar mass one are measured at room temperature for the investigated SPEs.

A temperature and redox‐responsive polymer hydrogel is constructed by randomly incorporating 2,2,6,6‐tetramethyl‐1‐piperidinyloxy‐methacrylate (TEMPO) stable nitroxide radicals and oligoethyleneglycol methacrylate (OEGMA) groups in a polymer network. TEMPO can be reversibly oxidized into an oxoammonium cation (TEMPO+) providing the redox‐responsive properties while the lower critical solubility temperature (LCST) of OEGMA results in temperature‐responsive properties. Since a rather low amount of di(ethylene glycol) dimethacrylate (OEGMA2) is used to chemically crosslink the polymer network, the accordingly formed hydrogels obtained after swelling with water consist of microgel particles with entangled polymer chains that are not chemically crosslinked. By varying the amount of TEMPO in the polymer network, it is demonstrated that the radical form of TEMPO aggregates into hydrophobic domains acting as physical crosslinking nodes in the hydrogels and further increasing the cohesion between microgel particles. Increasing the temperature results in two opposite effects on the solubility of TEMPO and OEGMA units. The oxidation of TEMPO into TEMPO+ also results in a deep change in the hydrogel properties since TEMPO+ units are essentially hydrophilic and do not aggregate into physical crosslinking nodes.

Fire-retardant electrolyte chemistries have attracted great attention given their potential to solve the grand challenges of alkali-ion batteries : safety, use of metallic anodes and anodic stability. Whereas extensive analysis and correlations are drawn to explain their unusual electrochemical behaviour, one essential property, their effects on redox potentials of battery components (redox potential shift) pervasively lack a strict description and quantification. Here we show that the strong solvation of lithium cations by organic phosphates, the widely used flame-retardant constituents, induces a negative redox potential shift by as much as 500mV. We demonstrate that the redox potential shift is characteristic of Li-cation (de)-solvation processes whereas negligible for other processes. This has important consequences for high energy hybrid battery concepts such as high voltage dual-ion graphite or organic batteries. These findings also shine a different light on the enhanced anodic stability of these non-conventional battery electrolyte formulations.

The linear and nonlinear rheology of associative colloidal polymer assemblies with metallo-supramolecular interactions is herein studied. Polystyrene-b-poly(tert-butylacrylate) with a terpyridine ligand at the end of the acrylate block is self-assembled into micelles in ethanol, a selective solvent for the latter block, and supramolecularly connected by complexation to divalent metal ions. The dependence of the system elasticity on polymer concentration can be semi-quantitatively understood by a geometrical packing model. For strongly associated (Ni2+, Fe2+) and sufficiently concentrated systems (15 w/v%), any given ligand end-group has a virtually 100% probability of being located in an overlapping hairy region between two micelles. By assuming a 50% probability of intermicellar crosslinks being formed, an excellent prediction of the plateau modulus was achieved and compared with the experimental results. For strongly associated but somewhat more dilute systems (12 w/v%) that still have significant overlap between hairy regions, the experimental modulus was lower than the predicted value, as the effective number of crosslinkers was further reduced along with possible density heterogeneities. The reversible destruction of the network by shear forces can be observed from the strain dependence of the storage and loss moduli. The storage moduli of the Ni2+ and Zn2+ systems at a lower concentration (12 w/v%) showed a rarely observed feature (i.e., a peak at the transition from linear to nonlinear regime). This peak disappeared at a higher concentration (15 w/v%). This behavior can be rationalized based on concentration-dependent network stretchability.

The principle of encapsulation/release of a guest molecule from stimuli responsive hydrogels (SRHs) is mainly realised with pH, temperature or light stimuli. However, only a limited number of redox responsive hydrogels have been investigated so far. We report here the development of a SRH that can release its guest molecule upon a redox stimulus. To obtain this redox hydrogel, we have introduced into the hydrogel the 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) stable nitroxide radical, which can be reversibly oxidized into an oxoammonium cation (TEMPO+). Water solubility is provided by the presence of the (oligoethyleneglycol)methacrylate (OEGMA) comonomer. Electrochemical and mechanical characterization showed that those gels exhibit interesting physicochemical properties, making them very promising candidates for practical use in a wide range of applications.

Recently, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA) has attracted intensive attention for energy storage applications. Organic radical batteries built with this polymer display high power performance. However, the solubility of PTMA in commercial electrolytes shortens the lifespan and the overall performance of the battery. To circumvent this issue, we propose to immobilize PTMA in a three-dimensional network. Indeed, an electrolyte swollen network (gel) enables a good ionic diffusion and brings good mechanical properties to the cathodic material. Here we report on the synthesis of PTMA gels by a combination of Cu(0)-mediated reversible-deactivation radical polymerization and copper-catalyzed azide–alkyne cycloaddition (CuAAC). The structure of the accordingly obtained gels is characterized by NMR, SEC and FTIR and the mechanical properties of these materials are studied by rheology. Finally, their electrochemical performances are studied in the context of organic radical batteries.

In this review, we highlight the progress realized in recent years on light-responsive polymers. More precisely, we provide some guidelines towards the rational design of photo-responsive block copolymers and we present the different photo-responsive moieties that have been used so far. We also discuss the different types of irreversible and reversible responses encountered by photo-responsive polymers. Finally, we discuss the application of light responsive polymers in material science.

Stimuli-responsive double hydrophilic diblock copolymers have been prepared that consist of poly(N-isopropylacrylamide)-block-poly(2-(dimethylamino)ethyl methacrylate) sequences terminated by a terpyridine ligand. These building blocks are assembled in aqueous media in a stepwise manner, by first forming metallo-supramolecular ABA triblock copolymers and then gels by thermo-induced micellar aggregation. This study sheds light on the subtle interplay that exists between the responsive behaviour of the core and corona forming blocks. Due to the intrinsic sensitivity of the constituting polymer chains and the non-covalent interactions between them, supramolecular gels respond to specific external triggers. These stimuli allow the manipulation of numerous rheological aspects of the assembled materials, including network formation and dynamics. Interestingly, an independent control over the network formation and dynamics is notably achieved via an appropriate choice of the metal ions and of the length of the associating block. By playing with the architecture of the associating copolymers and the nature of the metal ions, this work further demonstrates the possibility to build materials possessing either a mono or dual relaxation mechanism via a unique approach.

A nanostructured thin film obtained from a polystyrene-block-poly(4-vinylpyridine) diblock copolymer was used as a template to produce Janus-type nanoparticles. This was achieved by functionalizing the poly(4-vinylpyridine) microdomains with a diene molecule and by cross-linking them with diiodo compounds. A poly(methacrylate) chain end-functionalized by a triazolinedione group was selectively clicked onto the top of the poly(4-vinylpyridine) microdomains. The Janus nanoparticles were then released in solution by the dissolution of the thin film in a good solvent.

A new photo-sensitive diblock copolymer composed of a hydrophilic sequence of poly(ethylene oxide) (PEO) linked to a CO2-philic sequence of poly(1H,1H,2H,2H-heptadecafluorodecyl acrylate) (PFDA) by a light sensitive o-nitrobenzyl group was successfully synthesized by RAFT polymerization and used as a stabilizer for the free radical polymerization of 2-hydroxyethyl methacrylate (HEMA) dispersion in α,α,α-trifluorotoluene and supercritical carbon dioxide (scCO2). Thanks to this fluorinated stabilizer, well-defined particles of PHEMA down to 350 nm diameter were produced in scCO2. Advantageously, the photocleavable group at the block junction of the stabilizer could be cleaved by exposing the particles to UV light so that the fluorinated block could be extracted in TFT or scCO2. As supported by X-ray photoelectron spectroscopy (XPS) analysis, up to 80% of the fluorinated block of the stabilizer can be removed, leading to efficient swelling and dispersion of the resulting PHEMA nanogels in water.

This paper describes the synthesis and characterization of a new hybrid material based on poly(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate) (PTMA) for lithium battery applications. Our strategy relies on the anchoring of nitroxide-embedding polymer chains onto multi-walled carbon nanotubes (MWCNTs). The resulting hybrid material (MWCNT-g-PTMA) not only prevents the solubilization of the PTMA active material but also benefits from its structural design aspects. The MWCNT-g-PTMA structure confers high performances thanks to the precise distribution of the PTMA redox material with respect to the MWCNT conductive network, as confirmed by molecular modeling simulations of the polymer/MWCNT interface. Physicochemical characterizations are evidence of the success of MWCNT-g-PTMA synthesis with a polymer loading up to 30 wt%. Electrochemical analysis shows the potential of MWCNT-g-PTMA as a battery material, with a capacity reaching 85% of the theoretical value, a good cyclability (retention > 80% after 150 cycles) and excellent power performances (capacity at 60C exceeding 65% of the nominal value).

One of the first examples of supramolecular gels presenting independent dual dynamics is built through a combination of hydrophobic and metal-ligand interactions. The associating building block consists in a water-soluble linear polymer terminated by a short hydrophobic sticker at one end, and a coordinating moiety at the other end. The distinct supramolecular nature of these noninterfering binding motifs allows the dynamics of the hydrogels to be finely tuned in an orthogonal fashion by the application of specific stimuli. Precisely, the solvent-induced plasticization of the hydrophobic associations and the acid-promoted dissociation of the metal-ligand complexes are used to control the network dynamics. By opposition to classically encountered binary gel-sol responses, we demonstrate that the stimuli-induced transition in material properties can be gradual, provided that the material structure is well designed and strong enough.

Flexible portable electronic devices have attracted increasing attention during the last decade. Energy consumption of such devices is ever increasing and performing power sources, that are moreover flexible, need to be developed to seamlessly integrate into such architectures. While lithium-ion batteries appear to be the best solution to meet the power and energy requirements, their structural and mechanical considerations still need to be addressed. Here, we realize and study the impact on the electrochemical performances of carbon nanotubes (CNTs) based, current collector-free and binder-free, Li-ion battery electrodes. Multi-walled carbon nanotubes acting as a mechanical and electron conductive scaffold enable structural flexibility and good electrochemical performances. Flexible Li-ion cells made with such electrodes show promising performances while being realized through simple manufacturing approaches.

International audience; Solid polymer electrolytes are prepared by mixing various amounts of lithium bis(trifluoromethanesulfonyl)imide with poly(vinylidene fluoride‐co‐vinyl dimethyl phosphonate) statistical copolymers with different compositions. Such copolymers are obtained by conventional radical copolymerization of vinylidene fluoride (VDF) with vinyl dimethyl phosphonate (VDMP) initiated by peroxides. A morphological study of the obtained solid polymer electrolytes (SPEs) shows that only samples prepared from the copolymer with the lower amount of VDMP (16 mol%) result in the formation of homogeneous electrolytes while aggregates of lithium salts are observed for the other copolymers. The best ionic conductivity values are accordingly observed for the copolymers with the lower VDMP amount and are reaching 5 × 10−3 mS cm−1 at 100 °C. The dependence of the ionic conductivity versus temperature suggests that the ionic conductivity is controlled by the motion of polymer segments. Indeed, the ionic conductivity can be increased by adding a small amount of trimethylphosphate plasticizer and can reach 1.9 × 10−2 mS cm−1 at 20 °C. Finally, the prepared SPEs exhibit a high electrochemical stability and a good resistance to flame because of the presence of fire‐retardant phosphate groups in their structure.

A facile and novel method for the fabrication of core-shell nanoparticles (PTMA@SiO2) based on a poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA) core and a porous SiO2 shell is reported. The core-shell nanoparticles are further self-assembled with negatively charged multi-walled carbon nanotubes (MWCNTs), which results in the formation of a free-standing cathode electrode. The porous SiO2 shell not only effectively improves the stability of the linear PTMA redox polymer with low molar mass in organic electrolytes but also leads to the uniform dispersion of PTMA active units in the MWCNTs conductive network. The PTMA@SiO2@MWCNT composite electrode exhibits a specific capacity as high as 73.8 mAh g at 1 C and only 0.11% capacity loss per cycle at a rate of 2 C.

End-functionalized poly(3-hexylthiophene) (P3HT) and poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA) were synthesized using controlled polymerization techniques and linked together to lead to a diblock copolymer structure via click cycloaddition. These diblock copolymers were further blended with carbon nanotubes (CNTs) to be used as cathodes in organic radical batteries. The performances of these batteries were studied during charge/discharge cycling at constant and variable current densities (C rate). In order to shed light on the importance of the diblock copolymer architecture, the results were compared to the capacities measured on electrodes made of blends of P3HT and PTMA homopolymers. Theoretical simulations were finally used to corroborate the good electrochemical properties of the synthesized diblock copolymers.