Morphology Engineering of Self‐Assembled Nanostructured CuCo 2 O 4 Anodes for Lithium‐Ion Batteries

Carbonization of Corn Leaf Waste for Na-Ion Storage Application Using Water-Soluble Carboxymethyl Cellulose Binder

Hard carbon materials are considered to be the most practical anode materials for sodium ion batteries because of the rich availability of their resources and potentially low cost. Here, the conversion of corn leaf biomass, a largely available agricultural waste, into carbonaceous materials for Na-ion storage application is reported. Thermal analysis investigation determines the presence of exothermic events occurring during the thermal treatment of the biomass. Accordingly, various temperatures of 400, 500, and 600 °C are selected to perform carbonization treatment trials, leading to the formation of various biocarbons. The materials obtained are characterized by a combination of methods, including X-ray diffraction, electron microscopy, surface evaluation, Raman spectroscopy, and electrochemical characterizations. The Na-ion storage performances of these materials are investigated using water-soluble carboxymethyl cellulose binder, highlighting the influence of the carbonization temperature on the electrochemical performance of biocarbons. Moreover, the influence of post-mechanochemical treatment on the Na-ion storage performance of biocarbons is studied through kinetic evaluations. It is confirmed that reducing the particle sizes and increasing the carbon purity of biocarbons and the formation of gel polymeric networks would improve the Na-ion storage capacity, as well as the pseudocapacitive contribution to the total current. At a high-current density of 500 mA g-1, a specific Na-ion storage capacity of 134 mAh g-1 is recorded on the biocarbon prepared at 600 °C, followed by ball-milling and washing treatment, exhibiting a reduced charge transfer resistance of 49 Ω and an improved Na-ion diffusion coefficient of 4.8 × 10-19 cm2 s-1. This article proposes a simple and effective technique for the preparation of low-cost biocarbons to be used as the anode of Na-ion batteries.

Nanostructurally engineered TiO2 embedded Mentha aquatica biowaste derived carbon for supercapacitor applications

The invention of cost-effective, clean, and eco-friendly energy storage technology has been capturing a lot of worldwide interest. Herein, biogenically synthesized TiO₂ nanoparticles (NPs) were ultrasonically coupled with biomass-derived activated carbon (BAC) to obtain composite (denoted as TiO₂@BAC). With the inspiration of nature, Mentha Aquatica leaves extract was employed for biogenic preparation of TiO₂ NPs, and residual solid waste (SW) after extract was subsequently utilized for BAC. It is noteworthy that, this unique intensive method does not require any harmful or toxic chemicals and solvents, and no secondary waste is generated. TEM analysis of TiO₂@BAC revealed spherical morphology of TiO₂ NPs (average size ∼ 18 nm) that were accumulated on nanosheets. Raman, XRD, and XPS manifested the successful construction of TiO₂@BAC. The electrochemical performance of the as-synthesized BAC, TiO₂ NPs, and TiO₂@BAC electrodes was tested towards supercapacitor applications. Notably, the TiO₂@BAC electrode exhibited capacitance of 149 F/g at a current density of 1 A/g, which is approximately twice than that of the bare TiO₂ electrode (76 F/g) along with excellent capacitance restoration of ∼99%. The TiO₂@BAC electrode further revealed outstanding cyclic stability, exhibiting capacitance retention of ∼90% (at 5 A/g) after 10,000 charge/discharge cycles. Furthermore, the TiO₂@BAC electrode delivered optimal specific energy density (6.96 Wh/kg) and large power density (2.07 kW/kg at 10 A/g). Moreover, the TiO₂@BAC delivers an excellent restoration and retention performances of ∼100 and ∼95% (after 10,000 cycles) at 1 A/g with ∼98% coulombic efficiency in symmetric configuration (maximum cell voltage of 1.2 V).

Synthesis, Characterization and Applications of Spinel Cobaltite Nanomaterials

Recently, spinel structures (AB₂O₄) Nanoparticles (NPs) having binary and ternary mixtures of metal oxides have been established as promising redox catalysts. Due to the presence of two mixed valence metal cations, transport of electrons takes place easily between multiple transition-metal cations with relatively low energy of activation. Among these, spinel cobaltite (MCo₂O₄) is very attractive due to its low cost, non-toxicity, higher stability, higher electronic conductivity and electrochemical property. To date, MCo₂O₄ has been used in the fabrication of supercapacitors, electrodes for oxygen evolution reaction, and electrochemical sensors for glucose. A variety of MMCo₂O₄materials have been synthesized, characterized, and utilized in the fabrication of super capacitors, electrodes for oxygen evolution reaction, and electrochemical sensors for glucose. The progress in the field of the spinel MCo₂O₄ materials opens the door to novel and efficient applications in the nanoscience and nanotechnology, and elctrochemistry.

CuCo2O4 nanoparticles wrapped in a rGO aerogel composite as an anode for a fast and stable Li-ion capacitor with ultra-high specific energy

To meet practical application requirements, high specific energy and specific power and excellent cyclability are highly desired.

Urea assisted ceria nanocubes for efficient removal of malachite green organic dye from aqueous system

This study describes a simple, high-yield, rapid, and inexpensive route for the synthesis of cubic shape-like cerium oxide nanocubes (CeO₂ NCs) using different urea concentrations (0.5, 1.0, and 2.0 g) by the hydrothermal method. The synthesized nanocubes (NCs) are labeled as CeO₂ NCs-0.5, CeO₂ NCs-1.0, and CeO₂ NCs-2.0, corresponding to 0.5, 1.0, and 2.0 g of urea, respectively. The synthesized NCs were characterized by FT-IR, UV-visible, XRD, XPS, SEM and HR-TEM analysis. The synthesized NCs were cubic in shape with average sizes of 12, 12, and 13 nm for the CeO₂ NCs-0.5, CeO₂ NCs-1.0, and CeO₂ NCs-2.0, respectively, obtained by the XRD analysis. The catalytic activity of the CeO₂ NCs was studied for the purpose of obtaining the reduction of malachite green (MG) in the presence of sodium borohydride (NaBH₄) at room temperature.