Recently, aqueous
Zn-ion rechargeable batteries have drawn increasing
research attention as an alternative energy storage system relative
to the current Li-ion batteries due to their intrinsic properties
of high safety, low cost, and high theoretical volumetric capacity.
Nevertheless, unwanted dendrite growth on the Zn anode and unstable
cathode materials restrict their practical application. In this study,
a unique 2D MoS2 coating on a Zn anode using an electrochemical
deposition method has been developed for preventing dendrite growth
and intricate side reactions. The coated MoS2 layer is
a vertically oriented structure that makes the flow of Zn ions easy
with a uniform electric field distribution on the anode, resulting
in a uniform stripping and plating of Zn2+. In addition,
the MoS2 coating enhances anodic diffusion of Zn ions and
reduces the series resistance as confirmed by EIS analysis and therefore
improves the overall battery performance. The full cell assembled
with the MoS2–Zn anode and MnO2 cathode
exhibits an excellent reversible specific capacity of 638 mAh/g at
0.1 A/g and stable cycle performance over 2000 cycles with no dendrite
formation at the Zn electrode. The presented MoS2 coating
on Zn is a facile, scalable, and promising technology for practical
Zn-ion batteries with a long life cycle and high safety.
Polyurethane foams are in general flammable and their flammability can be controlled by adding flame-retardant (FR) materials. Reactive FR have the advantage of making strong bond within the polyurethane chains to provide excellent FR over time without compromising physico-mechanical properties. Here, phenyl phosphonic acid and propylene oxide-based reactive FR polyol was synthesized and used along with limonene based polyol for preparation of FR polyurethanes. All the obtained foams showed higher closed cell content (above 96%). By the addition of FR-polyol, the compressive strength of the foams showed 160% increment which could be due to reactive nature of FR-polyol. Moreover, 1.5 wt % of phosphorus (P) content reduced the self-extinguishing time of the foam from 81 (28% weight loss) to 11.2 s (weight loss of 9.8%). Cone test showed 68.6% reduction in peak heat release rate along with 23.4% reduction in thermal heat release. The change in char structure of carbon after burning was analyzed using Raman spectra which, suggests increment in the graphitic phase of the carbon over increased concentration of phosphorus. It can be concluded from this study that phosphorous based polyol could be blended with bio-based polyols to prepare highly FR and superior physico-mechanical rigid polyurethane foams.
Rapidly increasing markets for electric vehicles (EVs), energy storage for backup support systems and high-power portable electronics demand batteries with higher energy densities and longer cycle lives.
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