No abstract

Catechol-rich polymers are attractive for a plethora of applications but are difficult to synthesize in a controlled manner. Here, we describe a procedure for obtaining catechol homopolymers through the postpolymerization modification of RAFT-derived templates bearing active pentafluorophenyl esters. This protocol produces polymers with controllable molecular weight and low dispersity while suppressing the oxidation of the catechol units. The catechol homopolymers are electrochemically evaluated in both aqueous and organic media, where high reversibility of the catechol/quinone redox couple is observed. The procedure can be extended to cross-linked polymers by copolymerizing the template monomer with a divinyl unit, which leads to the formation of an insoluble network of active esters. This network can still undergo postpolymerization modification when swollen with a good solvent, and its reactivity is exploited to produce gels with catechol contents above 98%.

Organic electrodes are promising candidates for nextgeneration lithium-ion batteries due to their low cost and sustainable nature; however, they often suffer from very low conductivity and active material loadings. The conventional binder used in organic-based Li-ion batteries is poly(vinylidene fluoride) (PVDF), yet it is electrochemically inactive and thus occupies volume and mass without storing energy. Here, we report an organic mixed ionic-electronic conducting polymer, polyPEDOT-b-PEG for simplicity, as a cathode binder to address the aforementioned issues. The polymer contains a poly(3,4-ethylenedioxythiophene) (PEDOT) functionality to provide electronic conductivity, as well as poly(ethylene glycol) (PEG) chains to impart ionic conductivity to the cathode composite. We compare electrodes containing a perylene diimide (PDI) active material, conductive carbon, and a polymeric binder (either PVDF or PEDOT-b-PEG) with different weight ratios to study the impact of active material loading and type of binder on the performance of the cell. The lithium-ion cells prepared with the PEDOT-b-PEG polymer binder result in higher capacities and decreased impedance at all active material loadings compared to cathodes prepared with the PVDF-containing electrodes, demonstrating potential as a new binder to achieve higher active material loadings in organic electrodes. The strategy of preparing these polymers should be broadly applicable to other classes of mixed polymer conductors.

Templated oxidative polymerization affords organic soluble, oxidatively doped PEDOT-based polymers with controlled molecular weights and low dispersities (Đ ∼ 1.2) for the first time.