Conductive and stretchable materials that match the elastic moduli of biological tissue (0.5-500 kPa) are desired for enhanced interfacial and mechanical stability. Compared with inorganic and dry ...polymeric conductors, hydrogels made with conducting polymers are promising soft electrode materials due to their high water content. Nevertheless, most conducting polymer-based hydrogels sacrifice electronic performance to obtain useful mechanical properties. Here we report a method that overcomes this limitation using two interpenetrating hydrogel networks, one of which is formed by the gelation of the conducting polymer PEDOT:PSS. Due to the connectivity of the PEDOT:PSS network, conductivities up to 23 S m
are achieved, a record for stretchable PEDOT:PSS-based hydrogels. Meanwhile, the low concentration of PEDOT:PSS enables orthogonal control over the composite mechanical properties using a secondary polymer network. We demonstrate tunability of the elastic modulus over three biologically relevant orders of magnitude without compromising stretchability ( > 100%) or conductivity ( > 10 S m
).
Due to their high water content and macroscopic connectivity, hydrogels made from the conducting polymer PEDOT:PSS are a promising platform from which to fabricate a wide range of porous conductive ...materials that are increasingly of interest in applications as varied as bioelectronics, regenerative medicine, and energy storage. Despite the promising properties of PEDOT:PSS‐based porous materials, the ability to pattern PEDOT:PSS hydrogels is still required to enable their integration with multifunctional and multichannel electronic devices. In this work, a novel electrochemical gelation (“electrogelation”) method is presented for rapidly patterning PEDOT:PSS hydrogels on any conductive template, including curved and 3D surfaces. High spatial resolution is achieved through use of a sacrificial metal layer to generate the hydrogel pattern, thereby enabling high‐performance conducting hydrogels and aerogels with desirable material properties to be introduced into increasingly complex device architectures.
PEDOT:PSS hydrogels are an important framework for creating conductive porous materials that are of broad interest to researchers in the fields of bioelectronics, tissue engineering, stretchable electronics, and energy. To incorporate these materials into devices, a novel patterning method is presented that uses electrochemically produced ions to rapidly generate PEDOT:PSS hydrogel patterns with high spatial resolution.
Redox-active organic materials have gained growing attention as electrodes of rechargeable batteries. However, their key limitations are the low electronic conductivity and limited chemical and ...structural stability under redox conditions. Herein, we report a new cobalt-based 2D conductive metal–organic framework (MOF), Co-HAB, having stable, accessible, dense active sites for high-power energy storage device through conjugative coordination between a redox-active linker, hexaaminobenzene (HAB), and a Co(II) center. Given the exceptional capability of Co-HAB for stabilizing reactive HAB, a reversible three-electron redox reaction per HAB was successfully demonstrated for the first time, thereby presenting a promising new electrode material for sodium-ion storage. Specifically, through synthetic tunability of Co-HAB, the bulk electrical conductivity of 1.57 S cm–1 was achieved, enabling an extremely high rate capability, delivering 214 mAh g–1 within 7 min or 152 mAh g–1 in 45 s. Meanwhile, an almost linear increase of the areal capacity upon increasing active mass loading up to 9.6 mg cm–2 was obtained, demonstrating 2.6 mAh cm–2 with a trace amount of conducting agent.
Conductive metal–organic frameworks (c-MOFs) have shown outstanding performance in energy storage and electrocatalysis. Varying the bridging metal species and the coordinating atom are versatile ...approaches to tune their intrinsic electronic properties in c-MOFs. Herein we report the first synthesis of the oxygen analog of M3(C6X6)2 (X = NH, S) family using Cu(II) and hexahydroxybenzene (HHB), namely Cu-HHB Cu3(C6O6)2, through a kinetically controlled approach with a competing coordination reagent. We also successfully demonstrate an economical synthetic approach using tetrahydroxyquinone as the starting material. Cu-HHB was found to have a partially eclipsed packing between adjacent 2D layers and a bandgap of approximately 1 eV. The addition of Cu-HHB to the family of synthetically realized M3(C6X6)2 c-MOFs will enable greater understanding of the influence of the organic linkers and metals, and further broadens the range of applications for these materials.
Organic redox compounds represent an emerging class of cathode materials in rechargeable batteries for low-cost and sustainable energy storage. However, the low operating voltage (<3 V) and necessity ...of using lithium-containing anodes have significantly limited their practical applicability to battery systems. Here, we introduce a new class of p-type organic redox centers based on N,N'-substituted phenazine (NSPZ) to build ready-to-charge organic batteries. In the absence of lithium-containing anodes, NSPZ cathodes facilitate reversible two-electron transfer at 3.7 and 3.1 V accompanying anion association, which results in a specific energy of 622 Wh kg-1 in dual-ion batteries.
Organic electrodes have attracted significant attention as alternatives to conventional inorganic electrodes in terms of sustainability and universal availability in natural systems. However, low ...working voltages and low energy densities are inherent limitations in cathode applications. Here, we propose a high-energy organic cathode using a quinone-derivative, C6Cl4O2, for use in sodium-ion batteries, which boasts one of the highest average voltages among organic electrodes in sodium batteries (∼2.72 V vs Na/Na+). It also utilizes a two-electron transfer to provide an energy of 580 Wh kg–1. Density functional theory (DFT) calculations reveal that the introduction of electronegative elements into the quinone structure significantly increased the sodium storage potential and thus enhanced the energy density of the electrode, the latter being substantially higher than previously known quinone-derived cathodes. The cycle stability of C6Cl4O2 was enhanced by incorporating the C6Cl4O2 into a nanocomposite with a porous carbon template. This prevented the dissolution of active molecules into the surrounding electrolyte.
Carbon‐based nanomaterials such as graphene sheets and carbon nanotubes possess unique mechanical, electrical, and optical properties that present new opportunities for tissue engineering, a key ...field for the development of biological alternatives that repair or replace whole or a portion of tissue. Carbon nanomaterials can also provide a similar microenvironment as like a biological extracellular matrix in terms of chemical composition and physical structure, making them a potential candidate for the development of artificial scaffolds. In this review, we summarize recent research advances in the effects of carbon nanomaterial‐based substrates on cellular behaviors, including cell adhesion, proliferation, and differentiation into osteo‐ or neural‐ lineages. The development of 3D scaffolds based on carbon nanomaterials (or their composites with polymers and inorganic components) is introduced, and the potential of these constructs in tissue engineering, including toxicity issues, is discussed. Future perspectives and emerging challenges are also highlighted.
Carbon nanomaterials, such as graphene and carbon nanotubes, present new opportunities for tissue engineering applications because of their unique physicochemical properties. This Review summarizes recent studies on the interaction between carbon‐based nanomaterials and mammalian cells, such as cell adhesion, proliferation, and differentiation into osteo‐ or neural‐ lineages on graphene‐ or CNT‐based substrates.
A nanohybridization strategy is presented for the fabrication of high performance lithium ion batteries based on redox‐active organic molecules. The rearrangement of electroactive aromatic molecules ...from bulk crystalline particles into molecular layers is achieved by non‐covalent nanohybridization of active molecules with conductive scaffolds. As a result, nanohybrid organic electrodes in the form of a flexible self‐standing paper–free of binder/additive and current collector–are synthesized, which exhibit high energy and power densities combined with excellent cyclic stability.
Flavin Battery: Flavins are used as a molecularly tunable cathode material that reversibly reacts with two lithium ions and two electrons per formula unit. Combined ex situ analyses and DFT ...calculations reveal that the redox reaction occurs using two successive single‐electron transfer steps at nitrogen atoms of the diazabutadiene motif (see picture).
PDF
