In the archetypal lithium-rich cathode compound Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 , a major part of the capacity is contributed from the anionic (O 2−/− ) reversible redox couple and is accompanied by the transition metal ions migration with a detrimental voltage fade. A better understanding of these mutual interactions demands for a new model that helps to unfold the occurrences of voltage fade in lithium-rich system. Here we present an alternative approach, a cationic reaction dominated lithium-rich material Li 1.083 Ni 0.333 Co 0.083 Mn 0.5 O 2 , with reduced lithium content to modify the initial band structure, hence~80% and~20% of capacity are contributed by cationic and anionic redox couples, individually. A 400 cycle test with 85% capacity retention depicts the capacity loss mainly arises from the metal ions dissolution. The voltage fade usually from Mn 4+ /Mn 3+ and/or O n− /O 2− reduction at around 2.5/3.0 V seen in the typical lithium-rich materials is completely eliminated in the cationic dominated cathode material.
Thermal management has become one of the crucial factors in designing electronic equipment and therefore creating composites with high thermal conductivity is necessary. In this work, a new insight on hybrid filler strategy is proposed to enhance the thermal conductivity in Thermoplastic polyurethanes (TPU). Firstly, spherical aluminium oxide/hexagonal boron nitride (ABN) functional hybrid fillers are synthesized by the spray drying process. Then, ABN/TPU thermally conductive composite material is produced by melt mixing and hot pressing. Then, ABN/TPU thermally conductive composite material is produced by melt mixing and hot pressing. Our results demonstrate that the incorporation of spherical hybrid ABN filler assists in the formation of a three-dimensional continuous heat conduction structure that enhances the thermal conductivity of the neat thermoplastic TPU matrix. Hence, we present a valuable method for preparing the thermal interface materials (TIMs) with high thermal conductivity, and this method can also be applied to large-scale manufacturing.
MoO3/V2O5 hybrid nanobilayers are successfully prepared by the sol–gel method with a spin- coating technique followed by heat -treatment at 350 °C in order to achieve a good crystallinity. The composition, morphology, and microstructure of the nanobilayers are characterized by a scanning electron microscope (SEM) and X-ray diffractometer (XRD) that revealed the a grain size of around 20–30 nm, and belonging to the monoclinic phase. The samples show good reversibility in the cyclic voltammetry studies and exhibit an excellent response to the visible transmittance. The electrochromic (EC) window displayed an optical transmittance changes (ΔT) of 22.65% and 31.4% at 550 and 700 nm, respectively, with the rapid response time of about 8.2 s for coloration and 6.3 s for bleaching. The advantages, such as large optical transmittance changes, rapid electrochromism control speed, and excellent cycle durability, demonstrated in the electrochromic cell proves the potential application of MoO3/V2O5 hybrid nanobilayers in electrochromic devices.
Silicon-based anode materials are gaining popularity in lithium-ion battery research due to their high theoretical specific capacity compared to the conventional graphite anode. However, the commercialization of silicon-based anode materials has been hampered by their limited electronic conductivity and significant volume expansion. To address these challenges, our strategy was conducted to prepare porous silicon@carbon (p-Si@C) nanocomposites as an anode material using a simple aqueous solution method. In this work, nitrogen-containing p-phenylenediamine was chosen as the carbon source for synthesizing the nanostructured p-Si@C composites. The excellent electrochemical performance can be achieved, with over 100 cycles, a specific capacity of 624 mAh g −1 , and a high Coulombic efficiency of 97.2%. These promising results were attributed to efficient Li-ion transport and low volume expansion, which are confirmed by the distribution function of relaxation time plots coupled with impedance spectroscopy technique, followed by the calculation of the expansion rate obtained from the SEM cross-sectional image. Hence, our work not only clearly provides a simple yet valuable method for the preparation of nanostructured silicon-based anode material with good electrochemical performance but also demonstrates its potential for industrial battery-grade development.
The high capacity cathode materials with charge voltage above 4.5 V are widely being developed. To reduce surface reactivity at high voltage, Al2O3 and pullulan are used for coating on the Li(Li0.08Ni0.34Co0.08Mn0.5)O2 surface and are characterized by electrochemical analysis. Charge/discharge and electrochemical results reveal that the organic coating sustains in high voltage cycles. Ionic conductivity of surface coating plays a key role in the battery performance.
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