A process for gas-phase synthesis of titanium dioxide aerosol gels with controlled monomer size and crystalline phase using a diffusion flame aerosol reactor operated in a buoyancy-opposed configuration is disclosed. The process includes introducing a precursor stream into a diffusion flame aerosol reactor, introducing a fuel stream into the reactor, combusting the precursor stream and the fuel stream in a flame to form at least one nanoparticle, and operating the reactor in a down-fired buoyancy-opposed configuration to produce the aerosol gel.

A lanthanum molybdenum composite oxide is provided. The lanthanum molybdenum composite oxide has a primary crystal phase formed of La.sub.2Mo.sub.2O.sub.9. The lanthanum molybdenum composite oxide also has a secondary crystal phase formed of a lanthanum molybdenum composite oxide species other than La.sub.2Mo.sub.2O.sub.9. The secondary crystal phase may contain at least one species selected from a group consisting of La.sub.2Mo.sub.3O.sub.12, La.sub.6MoO.sub.12, La.sub.7Mo.sub.7O.sub.30, La.sub.2Mo.sub.4O.sub.15, La.sub.2MoO.sub.6, La.sub.4MoO.sub.9, and LaMo.sub.2O.sub.5.

A recovery method for a positive electrode active material includes: separating and recovering, from a positive electrode plate of a battery in which a positive electrode mixture containing a positive electrode active material is laminated on a positive electrode foil, the positive electrode mixture; supplying at least one of ozone and hydrogen peroxide to a slurry containing the positive electrode mixture to oxidize the positive electrode mixture; and separating and recovering the positive electrode active material from the slurry.

A film-forming powder containing a rare earth oxyfluoride has an average particle size D50 of 0.6-15 μm, a total volume of ≤10 μm pores of 0.51-1.5 cm.sup.3/g as measured by mercury porosimetry, and a BET surface area of 3-50 m.sup.2/g is suitable for forming a dense film in high yields or deposition rates and high productivity. The film-forming powder having a greater pore volume can be prepared by forming a rare earth ammonium fluoride complex salt on surfaces of rare earth oxide particles to provide precursor particles, and heat treating the precursor particles at a temperature of 350 to 700° C.

Provided are a sodium ion-conductive crystal-containing solid electrolyte sheet capable of giving excellent battery characteristics even when reduced in thickness, and an all-solid-state battery using the same. The solid electrolyte sheet contains at least one type of sodium ion-conductive crystal selected from β″-alumina and NASICON crystal and has a thickness of 500 μm or less and a flatness of 200 μm or less.

A coating material containing an oxyfluoride of yttrium and having a Fisher diameter of 1.0 to 10 μm and a tap density TD to apparent density AD ratio, TD/AD, of 1.6 to 3.5. The coating material preferably has a pore volume of pores with a diameter of 100 μm or smaller of 1.0 cm.sup.3/g or less as measured by mercury intrusion porosimetry. A coating containing an oxyfluoride of yttrium and having a Vickers hardness of 200 HV0.01 or higher. The coating preferably has a fracture toughness of 1.0×10.sup.2 Pa.Math.m.sup.1/2 or higher.

A method of manufacturing a gas sensor for detecting xylene is provided. A method of manufacturing a gas sensor includes reacting a mixed material including a first material containing a cobalt (Co) element and a second material containing a chromium (Cr) element to form a CoCr.sub.2O.sub.4 hollow structure having a hollow shape.

Provided are methods for synthesizing a graphene gel. In embodiments, such a method comprises flowing a graphene oxide composition comprising graphene oxide and a solvent, the solvent having a boiling point higher than pure water, through a reaction chamber under conditions to deoxygenate the graphene oxide and induce gelation to form a graphene gel suspended in the solvent and flowing through the reaction chamber.

A positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charging and discharging as compared with those of a known positive electrode active material. In order to form the positive electrode active material having the pseudo-spinel crystal structure in the charged state, it is preferable that a halogen source such as a fluorine and a magnesium source be mixed with particles of a composite oxide containing lithium, a transition metal, and oxygen, which is synthesized in advance, and then the mixture be heated at an appropriate temperature for an appropriate time.

The present disclosure relates to a cathode additive, a method for preparing the same, and a cathode and a lithium secondary battery including the same. More specifically, one embodiment of the present disclosure provides a cathode additive that can offset an irreversible capacity imbalance, increase the initial charge capacity of a cathode, and simultaneously inhibit the generation of a gas in a battery.