Aqueous zinc ion batteries (ZIBs) are promising energy storage devices due to the high ionic conductivity of the aqueous electrolyte as well as the safety, eco‐friendliness, and low cost. Vanadium ...oxide‐based materials are attractive cathode materials for aqueous ZIBs because of their high capacity from their layered structure and multiple valences. However, it is difficult to achieve high cycle stability and rate capability due to the low electrical conductivity and trapping of diffused electrolyte cations within the crystal structure, limiting the commercialization of aqueous ZIBs. In this study, the authors propose a facile sonochemical method for controlling the interlayer of the vanadate nanofiber crystal structure using poly(3,4‐ethylene dioxythiophene) (PEDOT) to overcome the shortcomings of vanadium oxide‐based materials. In addition, the electrochemical correlation between the interplanar distance of the expanded vanadate layers by the insertion of PEDOT and the behavior of Zn2+ ions is investigated. As a result, the intercalation of the conducting polymer increases the electron pathway and extends the distance of the vanadate layers, which helps to increase the number of active sites inside the vanadate and accelerate the zinc ion intercalation/de‐intercalation process. Their findings may guide research on the next generation of ZIBs that can replace lithium ion batteries.
The controlling interlayer of the vanadate nanofiber crystal structure using intercalation of conducting polymers is fabricated via a facile sonochemical method and used as a cathode material in zinc ion batteries. Intercalated conducting polymers act as strong pillars and facilitate rapid Zn2+ ion diffusion and electron transport, resulting in reversible electrochemical reactions and high rate performance.
Ni‐rich layered oxides are promising cathode materials for developing high‐energy lithium‐ion batteries. To overcome the major challenge of surface degradation, a TiO2 surface coating based on ...polydopamine (PDA) modification was investigated in this study. The PDA precoating layer had abundant OH catechol groups, which attracted Ti(OEt)4 molecules in ethanol solvent and contributed towards obtaining a uniform TiO2 nanolayer after calcination. Owing to the uniform coating of the TiO2 nanolayer, TiO2‐coated PDA‐LiNi0.6Co0.2Mn0.2O2 (TiO2‐PNCM) displayed an excellent electrochemical stability during cycling under high voltage (3.0–4.5 V vs. Li+/Li), during which the cathode material undergoes a highly oxidative charge process. In addition, TiO2‐PNCM exhibited excellent cyclability at elevated temperature (60 °C) compared with the bare NCM. The surface degradation of the Ni‐rich cathode material, which is accelerated under harsh cycling conditions, was effectively suppressed after the formation of an ultra‐thin TiO2 coating layer.
Lay(er)ing it on thick: Ni‐rich layered oxides are promising cathode materials for high‐energy lithium‐ion batteries. To achieve the stable electrochemical performance during cycling at high voltage (4.5 V), a uniform nano‐TiO2 coating layer is introduced with a precoating of polydopamine (PDA). The precoated PDA layer attracts Ti(OEt)4 molecules in the coating solution and helps to form a homogeneous TiO2 nanolayer after calcination.
Bioelectrodes have been developed to efficiently mediate electrical signals of biological systems as stimulators and recording devices. Recently, conductive hydrogels have garnered great attention as ...emerging materials for bioelectrode applications because they can permit intimate/conformal contact with living tissues and tissue‐like softness. However, administration and control over the in vivo lifetime of bioelectrodes remain challenges. Here, injectable conductive hydrogels (ICHs) with tunable degradability as implantable bioelectrodes are developed. ICHs were constructed via thiol‐ene reactions using poly(ethylene glycol)‐tetrathiol and thiol‐functionalized reduced graphene oxide with either hydrolyzable poly(ethylene glycol)‐diacrylate or stable poly(ethylene glycol)‐dimaleimide, the resultant hydrogels of which are degradable and nondegradable, respectively. The ICH electrodes had conductivities of 21–22 mS cm−1 and Young's moduli of 15–17 kPa, and showed excellent cell and tissue compatibility. The hydrolyzable conductive hydrogels disappeared 3 days after in vivo administration, while the stable conductive hydrogels maintained their shapes for up to 7 days. Our proof‐of‐concept studies reveal that electromyography signals with significantly improved sensitivity from rats could be obtained from the injected ICH electrodes compared to skin electrodes and injected nonconductive hydrogel electrodes. The ICHs, offering convenience in use, controllable degradation and excellent signal transmission, will have great potential to develop various bioelectronics devices.
The injectable conductive hydrogel electrodes, composed of functionalized poly(ethylene glycol) (PEG) polymers and Pluronic‐coated reduced graphene oxide, exhibit good electrical conductivity, softness, cell and tissue compatibility, and tunable degradability in vivo. These injectable conductive hydrogels displaying different degradation profiles are useful for implantable bioelectrodes.
Single-layer and few-layer transition metal dichalcogenides have been extensively studied for their electronic properties, but their energy-storage potential has not been well explored. This paper ...describes the structural and electrochemical properties of few-layer TiS2 nanocrystals. The two-dimensional morphology leads to very different behavior, compared to corresponding bulk materials. Only small structural changes occur during lithiation/delithiation and charge storage characteristics are consistent with intercalation pseudocapacitance, leading to materials that exhibit both high energy and power density.
Nuclear factor, erythroid 2-like 2 (Nrf2) is a master transcription factor for cellular defense against endogenous and exogenous stresses by regulating expression of many antioxidant and ...detoxification genes. Here, we show that Nrf2 acts as a key pluripotency gene and a regulator of proteasome activity in human embryonic stem cells (hESCs). Nrf2 expression is highly enriched in hESCs and dramatically decreases upon differentiation. Nrf2 inhibition impairs both the self-renewal ability of hESCs and re-establishment of pluripotency during cellular reprogramming. Nrf2 activation can delay differentiation. During early hESC differentiation, Nrf2 closely colocalizes with OCT4 and NANOG. As an underlying mechanism, our data show that Nrf2 regulates proteasome activity in hESCs partially through proteasome maturation protein (POMP), a proteasome chaperone, which in turn controls the proliferation of self-renewing hESCs, three germ layer differentiation and cellular reprogramming. Even modest proteasome inhibition skews the balance of early differentiation toward mesendoderm at the expense of an ectodermal fate by decreasing the protein level of cyclin D1 and delaying the degradation of OCT4 and NANOG proteins. Taken together, our findings suggest a new potential link between environmental stress and stemness with Nrf2 and the proteasome coordinately positioned as key mediators.
SiOx is a promising next‐generation anode material for lithium‐ion batteries. However, its commercial adoption faces challenges such as low electrical conductivity, large volume expansion during ...cycling, and low initial Coulombic efficiency. Herein, to overcome these limitations, an eco‐friendly in situ methodology for synthesizing carbon‐containing mesoporous SiOx nanoparticles wrapped in another carbon layers is developed. The chemical reactions of vinyl‐terminated silanes are designed to be confined inside the cationic surfactant‐derived emulsion droplets. The polyvinylpyrrolidone‐based chemical functionalization of organically modified SiO2 nanoparticles leads to excellent dispersion stability and allows for intact hybridization with graphene oxide sheets. The formation of a chemically reinforced heterointerface enables the spontaneous generation of mesopores inside the thermally reduced SiOx nanoparticles. The resulting mesoporous SiOx‐based nanocomposite anodes exhibit superior cycling stability (≈100% after 500 cycles at 0.5 A g−1) and rate capability (554 mAh g−1 at 2 A g−1), elucidating characteristic synergetic effects in mesoporous SiOx‐based nanocomposite anodes. The practical commercialization potential with a significant enhancement in initial Coulombic efficiency through a chemical prelithiation reaction is also presented. The full cell employing the prelithiated anode demonstrated more than 2 times higher Coulombic efficiency and discharge capacity compared to the full cell with a pristine anode.
A novel synthesis method of SiOx composite for high‐performance anode for lithium‐ion batteries is proposed. Synthesized SiOx composite shows intact hybridization of graphene oxide sheets with mesoporous nanoparticles made spontaneously by the thermal reduction process. These structural features significantly improve the electrochemical properties of SiOx. In addition, the commercialization possibility of composite through prelithiation and full‐cell test is confirmed.
Highly stretchable and cycle‐stable (high operando dynamic stretchable) zinc‐ion microbatteries that are nonharmful, environmentally friendly, and low cost are developed herein for the first time. ...Stretchable zinc‐ion microbatteries (SZIMBs) are fabricated by simultaneously incorporating the facile synthesis of conducting polymer‐intercalated vanadium oxide nanofibers as flexible and elastic cathode materials; the construction, design, and assembly of wavy‐type microdevices; and pre‐zincation techniques that break stereotypes. The poly(3,4‐ethylene dioxythiophene) (PEDOT)‐intercalated zinc vanadium oxide nanofiber zinc‐ion microbatteries (E‐ZVONF‐SZIMBs) manufactured by combining these strategies exhibit a maximum specific capacity of 0.16 mAh cm−2, high energy density of 0.112 mWh cm−2, and high power density of 3.5 mW cm−2 and maintain 83.7% of the initial specific capacity after 500 cycles. The E‐ZVONF‐SZIMBs maintain 78.9% of their initial specific capacity even after 7000 mechanical stretching/bending tests, exhibiting excellent operando dynamic stretchability. The stretchable zinc‐ion microbatteries show practical feasibility by maintaining 80% and 90% of the capacity at −20 and 60°C under 200% strain, respectively. These remarkable achievements in the field of stretchable zinc‐ion microbatteries are expected to have significant implications for the development of future device platforms.
Intercalating conducting polymers into the interlayer spacing of vanadate nanofibers, as cathode materials for stretchable zinc‐ion microbatteries (SZIMBs), enhances the electrochemical performance and elasticity of the vanadate structure. Short‐induced pre‐zincation (SIPZ) affords a thinner SZIMB anode, thereby enhancing the flexibility of wavy‐type SZIMBs. These combined approaches confer high stretchability and stable electrochemical performance to the SZIMBs, even under extreme environments.
Although fibroblasts are dormant in normal tissue, they exhibit explosive activation during wound healing and perpetual activation in pathologic fibrosis and cancer stroma. The key regulatory network ...controlling these fibroblast dynamics is still unknown. Here, we report that Twist1, a key regulator of cancer-associated fibroblasts, directly upregulates Prrx1, which, in turn, increases the expression of Tenascin-C (TNC). TNC also increases Twist1 expression, consequently forming a Twist1-Prrx1-TNC positive feedback loop (PFL). Systems biology studies reveal that the Twist1-Prrx1-TNC PFL can function as a bistable ON/OFF switch and regulates fibroblast activation. This PFL can be irreversibly activated under pathologic conditions, leading to perpetual fibroblast activation. Sustained activation of the Twist1-Prrx1-TNC PFL reproduces fibrotic nodules similar to idiopathic pulmonary fibrosis in vivo and is implicated in fibrotic disease and cancer stroma. Considering that this PFL is specific to activated fibroblasts, Twist1-Prrx1-TNC PFL may be a fibroblast-specific therapeutic target to deprogram perpetually activated fibroblasts.
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