Nanometer Sized Silver Particles Embedded Silica Particles—Spray Method

Spherical shaped, nanometer to micro meter sized silica particles were prepared in a homogeneous nature by spray technique. Silver nanoparticles were produced over the surface of the silica grains in a harmonized manner. The size of silver and silica particles was effectively controlled by the precursors and catalysts. The electrostatic repulsion among the silica spheres and the electro static attraction between silica spheres and silver particles make the synchronized structure of the synthesized particles and the morphological images are revealed by transmission electron microscope. The silver ions are reduced by sodium borohydride. Infra red spectroscopy and X-ray photoelectron spectroscopy analysis confirm the formation of silver–silica composite particles. Thermal stability of the prepared particles obtained from thermal analysis ensures its higher temperature applications. The resultant silver embedded silica particles can be easily suspended in diverse solvents and would be useful for variety of applications

Pyrolytic carbon derived from sorona as anode materials for Li ion batteries

343-348Carbonaceous materials are derived by the pyrolysis of sorona at 900°C. The structure and morphology of the materials are analyzed. Scanning electron microscopy (SEM) reveals the porogen free carbon show flake-like disordered materials. Thermal gravimetric analysis (TGA) and differential temperature analysis (DTA) of samples show the weight loss at around 100°C and 400°C attributed to loss of superficial moisture and destructive distillation of sorona. X-ray diffraction (XRD) studies of the pyrolytic carbon indicate the presence of small domains of coherent and parallel stacking of the graphene sheets. N2 adsorption analysis reveals an average Brunauer, Emmett and Teller (BET) surface area 3.59 m2/g for non-porogen sorona carbon. The prepared porogen sorona carbon is used as the anode materials for Li ion battery and electrochemical behavior is investigated. Charge-discharge test and cycling studies give good capacitive properties. The use of pyrolytic carbon derived from sorona as anode materials for lithium batteries is novel, inexpensive and simple

Electrocatalysts for Lithium-Air Batteries: Current Status and Challenges

In past decade, electrochemical energy storage gained undivided attention with the increase in electrical energy demand for the usage of new technology such as moveable electronics. Li-ion batteries (LIB) have been the most successful energy storage system with their long-life cycle and efficiency, lower energy density, and notable cost effectiveness with small-scale energy storage. However, with large-scale energy storage and for long duration, work still needs done to make LIB efficient on such a scale as well. Recently Li-air batteries have been suggested as potential energy storage systems that can provide the solution for large- and long-term electrical energy storage. The Li-air battery utilizes the catalyst-based redox reaction, and still, it is not applicable commercially due to low current density, poor life cycle, and energy efficiency. Generally, such problems are associated with the materials used as an electrocatalyst and on the selection of the electrolyte. Herein, we briefly review the current advancements in the field of electrocatalysts for Li-air batteries which hinders their improvement toward commercial applications, and this review also provides an outlook for future Li-air battery systems

Synthesis and characterization of aligned SiO2 nanosphere arrays: Spray method

The power of nanomaterials has been hampered by the difficulty in controlling their size and morphology. Monodispersed silica particles with different nanometer sizes synthesized by a novel spray method remove the obstacles for the commercialization of nanomaterials at a global level. The size and shape of the silica particles were effectively controlled by simple hydrolysis and condensation reaction. Morphological images (SEM and TEM) reveal the smooth and spherical shaped silica particles with homogeneous distribution. Structural and luminescence properties of the silica particles were examined by FT-IR absorption spectroscopy and photoluminescence. A very low weight percentile loss of the silica particle ensures its high thermal stability. The high surface areas of about 55 and 25 m2/g were achieved for 90 and 220 nm particle sized silica particles, respectively. The resultant silica particles can be easily suspended in water and would be useful for variety of applications

Two-Dimensional Mesoporous Cobalt Sulfide Nanosheets as a Superior Anode for a Li-Ion Battery and a Bifunctional Electrocatalyst for the Li–O₂ System

We report the synthesis of two-dimensional (2D) Co₃S₄ in a nanothickness sheetlike morphology via simple hydrothermal process and its application to electrochemical energy-storage devices. The presence of unique mesopores with a combination of core/shell nanoparticles in the nanosheets showed superior electrochemical performances as a negative electrode for a Li-ion battery (LIB) and an electrocatalyst in Li–O₂ battery applications. A high discharge capacity of ∼968 mAh g^–1 is noted after 60 cycles with excellent cycling stability when evaluated as an anode for a LIB. On the other hand, the first discharge capacity of ∼5917 mAh g^–1 is observed with a high reversibility of 95.72% for the Li–O₂ battery point of view. This exceptional electrochemical performance in both applications is mainly attributed to the presence of mesoporous with core/shell 2D nanostructure, which translates more catalytic bifunctional (oxygen reduction reaction/oxygen evolution reaction) active sites for Li–O₂ and sustains the volume variations that occur in a three-dimensional manner upon the charge–discharge process for LIB applications. <i>Ex situ</i> studies, such as transmission electron microscopy, X-ray photoelectron spectroscopy, and impedance spectroscopy studies, are also conducted to validate the reaction mechanisms