Redox-active catechols are bioinspired precursors for ortho-quinones that are characterized by higher discharge potentials than para-quinones, the latter being extensively used as organic cathode materials for lithium ion batteries (LIBs). Here, this study demonstrates that the rational molecular design of copolymers bearing catechol- and Li ion-conducting anionic pendants endow redox-active polymers (RAPs) with ultrarobust electrochemical energy storage features when combined to carbon nanotubes as a flexible, binder-, and metal current collector-free buckypaper electrode. The importance of the structure and functionality of the RAPs on the battery performances in LIBs is discussed. The structure-optimized RAPs can store high-capacities of 360 mA h g at 5C and 320 mA h g at 30C in LIBs. The high ion and electron mobilities within the buckypaper also enable to register 96 mA h g (24% capacity retention) at an extreme C-rate of 600C (6 s for total discharge). Moreover, excellent cyclability is noted with a capacity retention of 98% over 3400 cycles at 30C. The high capacity, superior active-material utilization, ultralong cyclability, and excellent rate performances of RAPs-based electrode clearly rival most of the state-of-the-art Li ion organic cathodes, and opens up new horizons for large-scalable fabrication of electrode materials for ultrarobust Li storage.

In this paper, we report the synthesis Via the Grignard metathesis method (GRIM) of donor/ acceptor double cable copolymers with diblock and random sequences, where the conjugated polythiophene backbone is substituted with hexyl chains and with alkyl chains bearing fullerene. First, the monomers 2,5-dibromo-3-hexylthiophene and 2,5-dibromo-3-(1,3-dioxa-2-octyl)thiophene were randomly copolymerized and yielded after the grafting of fullerene C 60 the double cable CoPTR-C. Second, the same monomers were used to synthesize a diblock copolymer with a block made from a random copolymerization of both monomers while the second block is pure poly(3-hexylthiophene). After the grafting of fullerene, the block double cable CoPTBl-C was obtained. Both double cable copolymers were investigated through various characterization methods. NMR 1D and 2D experiments allowed the full structural characterization and the determination of the final composition of the copolymers. The thermal behavior was investigated by TGA and DSC measurements, indicating that the incorporation of fullerene increased the thermal stability of the materials. The optical properties of these double cable copolymers were investigated by UV-visible absorption and fluorescence spectroscopy. The results showed no interaction at ground-state between the donor and acceptor moieties and a quenching of fluorescence of the polythiophene main chains in solution. AFM analysis on drop-casted films showed the dependence of the morphology of the double cable systems (random or diblock) on the aggregation.

International audienc

A CO2-sourced self-standing solid electrolyte membrane is prepared and evaluated for room temperature operating lithium batteries.

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α‐Alkylidene cyclic carbonates (αCCs) recently emerged as attractive CO2‐sourced synthons for the construction of complex organic molecules. Herein, we report the transformation of αCCs into novel families of sulfur‐containing compounds by organocatalyzed chemoselective addition of thiols, following a domino process that is switched on/off depending on the desired product. The process is extremely fast and versatile in substrate scope, provides selectively linear thiocarbonates or elusive tetrasubstituted ethylene carbonates with high yields following a 100 % atom economy reaction, and valorizes CO2 as a renewable feedstock. It is also exploited to produce a large diversity of unprecedented functional polymers. It constitutes a robust platform for the design of new sulfur‐containing organic synthons and important families of polymers.

Polycarbonates bearing linear carbonate linkages and polyether segments have demonstrated to be highly attractive solid electrolyte candidates for the design of safe energy storage devices, for example, lithium metal batteries. In this contribution, we are studying the influence of the introduction of some cyclic carbonate linkages within the polymer backbone on the electrolyte properties. We first describe the synthesis of polycarbonates/polyethers containing different contents of both linear and cyclic carbonate linkages within the chain by the copolymerization of a highly reactive CO2-based monomer (bis­(α-alkylidene cyclic carbonate)) with poly­(ethylene glycol) diol and a dithiol at room temperature. We then explore the influence of the content of the cyclic carbonates and the loading of the polymer by lithium bis­(trifluoromethane) sulfonimide (LiTFSI) on the electrolyte properties (glass transition and melting temperatures, ion conductivity, and diffusivity). The best electrolyte candidate is characterized by a linear/cyclic carbonate linkage ratio of 82/18 when loaded with 30 wt % LiTFSI. It exhibits an ion conductivity of 5.6 × 10–5 S cm–1 at 25 °C (7.9 × 10–4 S cm–1 at 60 °C), which surpasses by 150% (424% at 60 °C) the conductivity measured for a similar polymer bearing linear carbonate linkages only. It is also characterized by a high oxidation stability up to 5.6 V (vs Li/Li+). A self-standing membrane is then constructed by impregnating a glass fiber filter by this optimal polymer, LiTFSI, and a small amount of a plasticizer (tetraglyme). Cells are then assembled by sandwiching the membrane between a C-coated LiFePO4 (LFP) as the cathode and lithium as the anode and counter electrode. The cycling performances are evaluated at 0.1 C at 60 °C and room temperature for 40 cycles. Excellent cycling performances are noted with 100% of the theoretical capacity (170 mAh g–1) at 60 °C and 73.5% of the theoretical capacity (125 mAh g–1) at 25 °C.

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