Provided are hard carbon beads, their preparation method, and an energy storage device comprising the same. Microwave heating is used to synthesize cross-linked phenolic formaldehyde for reducing energy consumption and controlling the crosslinking density of cured phenolic formaldehyde. The problems caused by high temperature heating and hydrothermal process for curing resin can be solved by the instant disclosure, which can increase the economic values of electrode and energy storage device comprising the hard carbon beads.

Filled carbon nanotubes (CNTs) and methods of synthesizing the same are provided. An in situ chemical vapor deposition technique can be used to synthesize CNTs filled with metal sulfide nanowires. The CNTs can be completely and continuously filled with the metal sulfide fillers up to several micrometers in length. The filled CNTs can be easily collected from the substrates used for synthesis using a simple ultrasonication method.

Provided are a positive electrode active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery including the same, the positive electrode active material for a rechargeable lithium battery including a secondary particle in which a plurality of primary particles including a lithium nickel-based composite oxide are aggregated, wherein at least a portion of the primary particles are arranged radially, a boron coating layer on the surface of the secondary particles and containing lithium borate, and a boron-doped layer inside the primary particle exposed to the surface of the secondary particle.

A method of synthesizing a MXene material is provided. A starting MAX phase material can be selected, a reaction time and/or reaction temperature can be determined, and subsequently a MXene material can be generated through etching the MAX phase material in an etching solution based on at least one of the determined reaction time and/or reaction temperature. In some instances, the etching solution is an LiF/HCl solution.

The application provides a porous carbon block material having high elasticity and high sealing, and provides a method for preparing the same. Particularly, the present application provides a porous carbon block material, wherein the porous carbon block material has a pore size in the range of from 3 nm to 100 nm, a porosity of from 50% to 87%, and the pores in the material are closed pores. In addition, the application provides a method for preparing the porous carbon block material according to the present application. The porous carbon block material according to the present application has small pore size, high porosity, and closed pores, and thus has high strength combined with high elasticity, high sealing property, and low density. Hence, the porous carbon block material according to the present application may be used as a sealing material.

Provided are methods of effecting cation exchange in MXene materials so as to stabilize the materials. Also provided are compositions, comprising layered MXene materials that comprise an organic cation between layers. Also provided are MXene compositions comprising a chalcogen disposed thereon, the MXene composition further optionally comprising a quaternary ammonium halide disposed thereon.

A functionalized fibrous hierarchical zeolite includes a framework comprising aluminum atoms, silicon atoms, and oxygen atoms, the framework further comprising a plurality of micropores and a plurality of mesopores. The functionalized fibrous hierarchical zeolite is functionalized with at least one terminal hydroxyl. Terminal organometallic functionalities are bonded to silicon atoms of the microporous framework, the terminal organometallic functionalities comprising a nickel atom.

The present invention relates to novel sulfur-doped carbonaceous porous materials. The present invention also relates to processes for the preparation of these materials and to the use of these materials in applications such as gas adsorption, mercury and gold capture, gas storage and as catalysts or catalyst supports.

Copper sulfide of the formula Cu.sub.xS.sub.y, wherein x and y are integer or non-integer values, wherein (i) the copper sulfide has a sulfur 2p XPS spectrum with peaks at 162.3 eV (±1 ev), 163.8 eV (±1 ev) and 68.5 eV (±1 ev), characterised in that the peak at 168.5 eV has a lower value of counts per second (CPS) than both the peak at 162.3 eV and the peak at 163.8 eV; and (ii) the copper sulfide has a copper 2p XPS spectrum with peaks at 932.0 eV (±2 ev) and 933.6 eV (±3 eV) and characterised in that the XPS spectrum does not comprise identifiable satellite peaks at 939.8 eV and 943.1 eV (±3 eV).

A semiconductor sintered body comprising a polycrystalline body, wherein the polycrystalline body includes silicon or a silicon alloy, wherein the average grain size of the crystal grains forming the polycrystalline body is 1 μm or less, and wherein nanoparticles including one or more of a carbide of silicon, a nitride of silicon, and an oxide of silicon are present at a grain boundary of the grains.