Provided is a carbonaceous material for a negative electrode active material additive for a lithium secondary battery, which has D.sub.v50 of 6 m or less and D.sub.n50 of 1 m or less. According to the carbonaceous material for a negative electrode active material additive for a lithium secondary battery of an embodiment of the present invention, since lithium ions may be rapidly adsorbed to and desorbed from a negative electrode adopting the carbonaceous material, output characteristics of a lithium secondary battery including the carbonaceous material are improved, and since a decrease in a capacity is small even when repeatedly charged and discharged, life characteristics are excellent.

Provided are: composite particles having excellent oxidation resistance; and a method for producing composite particles. The composite particles are obtained by forming a composite of TiC and at least one of Zr and Si. In the method for producing composite particles, a titanium oxide powder and at least one of a zirconium oxide powder and a silicon oxide powder are used as raw material powders, and composite particles are produced using a gas phase method.

Provided are methods of stabilizing MXene compositions using polyanionic salts so as to reduce the oxidation of the MXenes. Also provided are stabilized MXene compositions.

Provided are methods of stabilizing MXene compositions using polyanionic salts so as to reduce the oxidation of the MXenes. Also provided are stabilized MXene compositions.

A process for preparing transition metal carbonates with a mean particle diameter in the range from 6 to 19 m (D50), which comprises combining, in a stirred vessel, at least one solution of at least one transition metal salt with at least one solution of at least one alkali metal carbonate or alkali metal hydrogencarbonate to prepare an aqueous suspension of transition metal carbonate, and, in at least one further compartment, continuously introducing a mechanical power in the range from 50 to 10 000 W/l in a proportion of the suspension in each case, based on the proportion of the suspension, and then recycling the proportion into the stirred vessel.

A process for preparing transition metal carbonates with a mean particle diameter in the range from 6 to 19 m (D50), which comprises combining, in a stirred vessel, at least one solution of at least one transition metal salt with at least one solution of at least one alkali metal carbonate or alkali metal hydrogencarbonate to prepare an aqueous suspension of transition metal carbonate, and, in at least one further compartment, continuously introducing a mechanical power in the range from 50 to 10 000 W/l in a proportion of the suspension in each case, based on the proportion of the suspension, and then recycling the proportion into the stirred vessel.

The disclosure provides an MAX phase material, a preparation method therefor, and application thereof. The molecular formula of the MAX phase material is represented as M.sub.n+1(A.sub.zA.sub.1z).sub.hX.sub.n, wherein M is selected from group IIIB, IVB, VB or VIB elements, A is selected from element Zn, Cu, Ni, Co, Fe or Mn, A is selected from group IB, IIB, VIII, IVA, VA or VIA elements, X is selected from elements C and/or N, n is 1, 2, 3 or 4, 0<z1, a unit cell of the MAX phase material is formed by alternately stacking M.sub.n+1X.sub.n units and (A.sub.zA.sub.zA.sub.1z).sub.h layers of atoms, and h is the number of layers of the (A.sub.zA.sub.zA.sub.1z) layers of atoms located between the M.sub.n+1X.sub.n unit layers, and h is 1, 2 or 3.

A method of forming a carbonized composition includes providing an organic composition, forming a protective layer over the organic composition, increasing temperature to carbonize the organic composition and for a period of time to form the carbonized composition, and removing the protective layer from the carbonized composition.

A method of forming a carbonized composition includes providing an organic composition, forming a protective layer over the organic composition, increasing temperature to carbonize the organic composition and for a period of time to form the carbonized composition, and removing the protective layer from the carbonized composition.

Disclosed herein are electrochemical cells comprising electrodes prepared from layered materials omprising a substantially two-dimensional ordered array of cells having an empirical formula of M.sub.n+1X.sub.n, where M comprises a transition metal selected from the group consisting of a Group IIIB metal, a Group IVB metal, a Group VB metal, a Group VIB metal, and any combination thereof, X is C.sub.xN.sub.y wherein x+y=n, and n is equal to 1, 2, or 3. Also disclosed herein are batteries comprising the electrochemical cells and methods for electrochemically preparing MXene compositions with the use of the electrochemical cells.