The promising prospects of the Li/S battery, due to its theoretical energy density of about 2500 Wh kg ─1 , are severely limited by two main weaknesses: the poor conductivity of S and the solubility of the polysulphides in the electrolyte. A combination of carbon and transition metal oxides is the best option for mitigating both of these shortcomings simultaneously. In this work, we use hydrothermally-tailored γ-MnO 2 nanorods combined with an activated biomass-derived carbon, which is an inexpensive material and easy to prepare. This strategy was also followed for a AC/MnO 2 /S composite, a preparation of which was made by grinding; this is the simplest method for practical applications. More complex procedures for the formation of in situ hydrothermal MnO 2 nanorods gave similar results to those obtained from grinding. Compared with the AC/S composite, the presence of MnO 2 markedly increased the delivered capacity and improved the cycling stability at both low (0.1 C) and high (1 C) currents. This behaviour results from a combination of two main effects: firstly, the MnO 2 nanorods increase the electrical conductivity of the electrode, and secondly, the small particle size of the oxide can enhance the chemisorption properties and facilitate a redox reaction with polysulphides, more efficiently blocking their dissolution in the electrolyte.
The huge consumption of rechargeable Li‐ion batteries (LIBs) make it necessary to recover and reuse the different components of spent batteries, thus favoring sustainable development. Graphite is a critical material in the manufacture of the current LIBs so recycling it should be prioritized in the management of spent batteries. In this work, graphite is manually recovered from spent batteries used in smartphones. The impurities from the different components of the batteries are drastically reduced by simple leaching with HCl. This treatment significantly improves the delivered specific capacity, with average values of 300 and 390 mAh g−1 without and with leaching, respectively. To test recycled graphite as an anode material in real cells, it is paired with LiNi0.5Mn1.5O4, the most promising cathode material for high‐voltage batteries. LiCl, produced directly by chlorination of spodumene, is used as the Li source to obtain the spinel sample. The real cell gives satisfactory values for both initial specific capacity (100 mAh g−1) and capacity retention after 100 cycles. These results are comparable to and in some cases even better than those for cells that use commercial graphite and conventional Li sources as primary raw materials. Moreover, the cell shows good performance during the rate capability test; the delivered capacity values decrease smoothly from 73 to 62 mAh g−1 while the rate increases from 0.1 to 1 C.
Disordered carbons derived from banana peel waste (BPW) were successfully obtained by employing a simple one-step activation/carbonization method. Different instrumental techniques were used to characterize the structural, morphological, and textural properties of the materials, including X-ray diffraction, thermogravimetric analysis, porosimetry and scanning electron microscopy with energy-dispersive X-ray spectroscopy. The chemical activation with different porogens (zinc chloride, potassium hydroxide and phosphoric acid) could be used to develop functional carbonaceous structures with high specific surface areas and significant quantities of pores. The BPW@H3PO4 carbon exhibited a high specific surface area (815 m2 g−1), chemical stability and good conductivity for use as an anode in lithium-ion batteries. After 200 cycles, this carbon delivered a reversible capacity of 272 mAh g−1 at 0.2 C, showing a notable retention capacity and good cycling performance even at high current densities, demonstrating its effectiveness and sustainability as an anode material for high-energy applications in Li-ion batteries.
A protein-templated
titania nanocomposite (PT-TiO2)
was successfully synthesized by a water-free mechanochemical approach.
A biomass valorization strategy was developed by employing egg white
from expired eggs to control the morphology and textural features
of the prepared titania. A remarkable enhancement of the surface area
was achieved, in comparison with the synthesis of the material in
absence of the biomass-derived template. Several techniques, such
as scanning electron microscopy-mapping and CNHS analysis, supported
the presence of carbon, nitrogen and sulfur residues in the obtained
composite. Catalytic performance of PT-TiO2 was explored
in the oxidation of diphenyl sulfide, displaying promising results
in terms of conversion, selectivity and stability. The effect of the
oxidant agent was additionally investigated by using hydrogen peroxide,
urea hydrogen peroxide, oxygen and t-butyl-hydroperoxide.
On the other hand, PT-TiO2 nanocomposite was successfully
proved as anodic material for lithium-ion batteries delivering a reversible
capacity of 107 mAh g–1 at 0.1C with an excellent
Coulombic efficiency of 100% from the second cycle. In addition, the
as-synthesized material showed significant capacity retention values
of 76% among the 2nd cycle and 100th cycle. PT-TiO2 resulted
to be a versatile material with potential catalytic and energy storage
applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.