Provided are a method of preparing a metal oxide-silica composite aerogel, and a metal oxide-silica composite aerogel having an excellent weight reduction property prepared by the method. The method includes a step of adding an acid catalyst to a first water glass solution to prepare an acidic water glass solution (step 1); a step of adding a metal ion solution to the acidic water glass solution to prepare a precursor solution (step 2); and a step of adding a second water glass solution to the precursor solution and performing a gelation reaction (step 3) to yield a metal oxide-silica composite wet gel, wherein, in steps 2 and 3, bubbling of an inert gas is performed during the adding of the metal ion solution or the second water glass solution, respectively.

The present disclosure provides supercapacitors that may avoid the shortcomings of current energy storage technology. Provided herein are electrochemical systems, comprising three dimensional porous reduced graphene oxide film electrodes. Prototype supercapacitors disclosed herein may exhibit improved performance compared to commercial supercapacitors. Additionally, the present disclosure provides a simple, yet versatile technique for the fabrication of supercapacitors through the direct preparation of three dimensional porous reduced graphene oxide films by filtration and freeze casting.

A silicon-carbon composite material includes a matrix core, a silicon-carbon composite shell formed by uniformly dispersing nano silicon particles in conductive carbon, and a coating layer. The nano silicon particles are formed by high-temperature pyrolysis of a silicon source, and the conductive carbon is formed by high-temperature pyrolysis of an organic carbon source. The coating layer is a carbon coating layer including at least one layer, and the thickness of its single layer is 0.2-3 μm. A silicon-carbon composite material precursor is formed by simultaneous vapor deposition and is then subjected to carbon coating to form the pitaya-like silicon-carbon composite material which has advantages of high first-cycle efficiency, low expansion and long cycle. The grain growth of the silicon material is slowed down during the heat treatment process, the pulverization of the material is effectively avoided, and the cycle performance, conductivity and rate performance of the material are enhanced.

Provided are nanocrystalline graphene and a method of forming the nanocrystalline graphene through a plasma enhanced chemical vapor deposition process. The nanocrystalline graphene may have a ratio of carbon having an sp.sup.2 bonding structure to total carbon within the range of about 50% to 99%. In addition, the nanocrystalline graphene may include crystals having a size of about 0.5 nm to about 100 nm.

Treated, mesoporous aggregates comprising a plurality of coated particles that comprise an inorganic oxide core having a surface area of about 50 to about 500 square meters per gram and a shell or coating consisting of an array of fluoroalkyl molecular chains covalently bonded to the core at a density of at least one chain per square nanometer. The aggregates are formed by the chemical attachment of fluoroalkyl-alkylsilanes after exposure to an alkylamine and followed by an extraction to remove any unbound organic material. The dense packing of molecular chains in the fluoroalkyl shell combined with a mesoporous structure imparts a very low surface energy, a very high specific surface area, and surface texture over a wide range of length scales. Such features are highly desirable for the creation of, for example, superhydrophobic and superoleophobic surfaces, separation media, and release films.

A highly purified diatomite composition may include greater than or equal to 90% silica, from about 0.5% to about 5% of a calcium-containing compound, and less than or equal to about 2% total of aluminum-containing oxides and iron-containing oxides. A method of making a highly purified diatomite composition may include providing a diatomite comprising at least 5% of a calcium-containing compound, calcining the diatomite, and acid washing the calcined diatomite. The calcined, acid-washed diatomite may include less than or equal to about 1% total of extractable aluminum-containing oxides and iron-containing oxides, and less than or equal to about 5% of the calcium-containing compound. The acid washing may include an acid selected from the group consisting of sulfuric acid (H.sub.2SO.sub.4), hydrochloric acid (HCl), and nitric acid (HNO.sub.3). The method may not include a flotation step.

Disclosed are methods for producing carbon foam in which using the vitrinite reflectance values of coals are used to form a blended coal precursor having a targeted vitrinite reflectance value. The targeted vitrinite reflectance value can be used to create similar carbon foam products from one production batch to the next.

A positive electrode active material for a nonaqueous electrolyte secondary battery is used for a nonaqueous electrolyte secondary battery. The positive electrode active material includes a composite oxide containing at least lithium, nickel, and manganese and contains aggregated particles of primary particles having an average particle diameter of 1.0 μm or more. The primary particles have a layered crystal structure and a spinel crystal structure.

A cathode material with oxygen vacancy is provided. The cathode material includes a lithium metal phosphate compound having a general formula LiMPO.sub.4-Z, wherein M represents at least one of a first-row transition metal, and 0.001≦z≦0.05.

A preparation method of an ant nest like porous silicon for a lithium-ion battery comprises: (1) enabling a magnesium silicide raw material to react for 2-24 h in an ammonia gas or an atmosphere containing an ammonia gas at 600-900° C. to obtain a crude product containing porous silicon; and (2) subjecting the crude product containing porous silicon to an acid pickling treatment to obtain the ant nest like porous silicon. The preparation method has the advantages of simplicity and easiness. A large amount of porous silicon can be obtained by directly heating the magnesium silicide raw material in the ammonia gas or a mixed gas of the ammonia gas and an inert gas with a high yield.