High-performance all-solid-state supercapacitors (SCs) are fabricated based on thin, lightweight, and flexible freestanding MVNN/CNT hybrid electrodes. The device shows a high volume capacitance of 7.9 F/cm(3) , volume energy and power density of 0.54 mWh/cm(3) and 0.4 W/cm(3) at a current density of 0.025 A/cm(3) . By being highly flexible, environmentally friendly, and easily connectable in series and parallel, the all-solid-state SCs promise potential applications in portable/wearable electronics.
Polymer binders with high ion and electron conductivities are prepared by assembling ionic polymers (polyethylene oxide and polyethylenimine) onto the electrically conducting polymer poly(3,4‐ethylenedioxythiophene): poly(styrenesulfonate) chains. Crosslinking, chemical reductions, and electrostatics increase the modulus of the binders and maintain the integrity of the anode. The polymer binder shows lithium‐ion diffusivity and electron conductivity that are 14 and 90 times higher than those of the widely used carboxymethyl cellulose (with acetylene black) binder, respectively. The silicon anode with the polymer binder has a high reversible capacity of over 2000 mA h g−1 after 500 cycles at a current density of 1.0 A g−1 and maintains a superior capacity of 1500 mA h g−1 at a high current density of 8.0 A g−1.
Electrical interactions between bacteria and the environment are delicate and essential. In this study, an external electrical current is applied to capacitive titania nanotubes doped with carbon (TNT-C) to evaluate the effects on bacteria killing and the underlying mechanism is investigated. When TNT-C is charged, post-charging antibacterial effects proportional to the capacitance are observed. This capacitance-based antibacterial system works well with both direct and alternating current (DC, AC) and the higher discharging capacity in the positive DC (DC+) group leads to better antibacterial performance. Extracellular electron transfer observed during early contact contributes to the surface-dependent post-charging antibacterial process. Physiologically, the electrical interaction deforms the bacteria morphology and elevates the intracellular reactive oxygen species level without impairing the growth of osteoblasts. Our finding spurs the design of light-independent antibacterial materials and provides insights into the use of electricity to modify biomaterials to complement other bacteria killing measures such as light irradiation.
Binder plays a key role in maintaining the mechanical integrity of electrodes in lithium-ion batteries. However, the existing binders typically exhibit poor stretchability or low conductivity at large strains, which are not suitable for highcapacity silicon (Si)-based anodes undergoing severe volume changes during cycling. Herein, a novel stretchable conductive glue (CG) polymer that possesses inherent high conductivity, excellent stretchablity, and ductility is designed for high-performance Si anodes. The CG can be stretched up to 400% in volume without conductivity loss and mechanical fracture and thus can accommodate the large volume change of Si nanoparticles to maintain the electrode integrity and stabilize solid electrolyte interface growth during cycling while retaining the high conductivity, even with a high Si mass loading of 90%. The Si-CG anode has a large reversible capacity of 1500 mA h g −1 for over 700 cycles at 840 mA g −1 with a large initial Coulombic efficiency of 80% and high rate capability of 737 mA h g −1 at 8400 mA g −1 . Moreover, the Si-CG anode demonstrates the highest achieved areal capacity of 5.13 mA h cm −2 at a high mass loading of 2 mg cm −2 . The highly stretchable CG provides a new perspective for designing next-generation high-capacity and high-power batteries.
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