Charge transport processes in nonconjugated redox-active polymers with electrolytes were studied using a diffusion-cooperative model. For the first time, we quantitatively rationalized that the limited Brownian motion of the redox centers bound to the polymers resulted in the 10-fold decline of the bimolecular and heterogeneous charge transfer rate constants, which had been unexplained for half a century. As a next-generation design, a redox-active supramolecular system with high physical mobility was proposed to achieve the rate constant as high as in free solution system (>10 M s) and populated site density (>1 mol/L).
For
rapid charging of lithium-ion batteries, a series of novel electrode-active
materials have been studied. However, those materials suffered from
replacing conventional metal oxides, such as LiCoO2 and
LiFePO4, because of the strict performance criteria for
commercialization. As an alternative approach, we propose the hybridization
of the conventional inorganic active materials with organic redox-active
polymers which are characterized by fast electrode kinetics. A new
robust organic-radical-substituted polyether was synthesized to yield
one of the highest charge transportabilities of nonconjugated polymers
with a charge diffusion coefficient of 10–7 cm2/s. The hybrid electrode of LiFePO4 and a small
amount of the polymer was able to be charged within several minutes
by virtue of the electrocatalytic oxidation of the metal oxide with
the radical polymer. In addition, several 4 V class organic redox-active
polymers were synthesized for the hybrid with LiCoO2. After
hybridization, the LiCoO2 electrodes could also be charged
within several minutes with the reduced overvoltages.
A highly flexible yet high‐energy‐density cathode for lithium‐ion batteries is fabricated with a novel redox‐active binder polymer composed of 2,2,6,6‐tetramethylpiperidine 1‐oxyl (TEMPO) with vinyl ether main chain, lithium cobalt oxide, and single‐walled carbon nanotube. The cathode itself and its battery display excellent durability against repeated bending over 104 times. The highest volumetric capacity beyond 300 mAh cm−3 as a flexible electrode is achieved based on the highly adhesive and redox‐active, robust radical polyether binder. A highly flexible, only 0.5 mm‐thick, lithium‐ion battery charge/discharges repeatedly with constant output around 3.8 V even under rapid bending. Herein, the operation of flexible electronic devices with well‐balanced energy density and power‐supplying purposes is discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.